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<a name="1" href="#1">1</a>   <strong>package</strong> <a href="../../../../org/apache/torque/util/package-summary.html">org.apache.torque.util</a>;
<a name="2" href="#2">2</a>   
<a name="3" href="#3">3</a>   <em class="comment">/*</em>
<a name="4" href="#4">4</a>   <em class="comment"> * Licensed to the Apache Software Foundation (ASF) under one</em>
<a name="5" href="#5">5</a>   <em class="comment"> * or more contributor license agreements.  See the NOTICE file</em>
<a name="6" href="#6">6</a>   <em class="comment"> * distributed with this work for additional information</em>
<a name="7" href="#7">7</a>   <em class="comment"> * regarding copyright ownership.  The ASF licenses this file</em>
<a name="8" href="#8">8</a>   <em class="comment"> * to you under the Apache License, Version 2.0 (the</em>
<a name="9" href="#9">9</a>   <em class="comment"> * "License"); you may not use this file except in compliance</em>
<a name="10" href="#10">10</a>  <em class="comment"> * with the License.  You may obtain a copy of the License at</em>
<a name="11" href="#11">11</a>  <em class="comment"> *</em>
<a name="12" href="#12">12</a>  <em class="comment"> *   <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
<a name="13" href="#13">13</a>  <em class="comment"> *</em>
<a name="14" href="#14">14</a>  <em class="comment"> * Unless required by applicable law or agreed to in writing,</em>
<a name="15" href="#15">15</a>  <em class="comment"> * software distributed under the License is distributed on an</em>
<a name="16" href="#16">16</a>  <em class="comment"> * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY</em>
<a name="17" href="#17">17</a>  <em class="comment"> * KIND, either express or implied.  See the License for the</em>
<a name="18" href="#18">18</a>  <em class="comment"> * specific language governing permissions and limitations</em>
<a name="19" href="#19">19</a>  <em class="comment"> * under the License.</em>
<a name="20" href="#20">20</a>  <em class="comment"> */</em>
<a name="21" href="#21">21</a>  
<a name="22" href="#22">22</a>  <strong>import</strong> java.io.IOException;
<a name="23" href="#23">23</a>  <strong>import</strong> java.io.ObjectInputStream;
<a name="24" href="#24">24</a>  <strong>import</strong> java.io.Serializable;
<a name="25" href="#25">25</a>  <strong>import</strong> java.lang.reflect.Method;
<a name="26" href="#26">26</a>  <strong>import</strong> java.sql.Connection;
<a name="27" href="#27">27</a>  <strong>import</strong> java.sql.SQLException;
<a name="28" href="#28">28</a>  <strong>import</strong> java.util.ArrayList;
<a name="29" href="#29">29</a>  <strong>import</strong> java.util.Hashtable;
<a name="30" href="#30">30</a>  <strong>import</strong> java.util.Iterator;
<a name="31" href="#31">31</a>  <strong>import</strong> java.util.List;
<a name="32" href="#32">32</a>  <strong>import</strong> java.util.Set;
<a name="33" href="#33">33</a>  
<a name="34" href="#34">34</a>  <strong>import</strong> org.apache.commons.logging.Log;
<a name="35" href="#35">35</a>  <strong>import</strong> org.apache.commons.logging.LogFactory;
<a name="36" href="#36">36</a>  <strong>import</strong> org.apache.torque.Torque;
<a name="37" href="#37">37</a>  <strong>import</strong> org.apache.torque.TorqueException;
<a name="38" href="#38">38</a>  
<a name="39" href="#39">39</a>  <strong>import</strong> com.workingdogs.village.DataSetException;
<a name="40" href="#40">40</a>  <strong>import</strong> com.workingdogs.village.QueryDataSet;
<a name="41" href="#41">41</a>  
<a name="42" href="#42">42</a>  <em>/**<em>*</em></em>
<a name="43" href="#43">43</a>  <em> * This class can be used to retrieve a large result set from a database query.</em>
<a name="44" href="#44">44</a>  <em> * The query is started and then rows are returned a page at a time.  The &lt;code></em>
<a name="45" href="#45">45</a>  <em> * LargeSelect&lt;/code> is meant to be placed into the Session or User.Temp, so</em>
<a name="46" href="#46">46</a>  <em> * that it can be used in response to several related requests.  Note that in</em>
<a name="47" href="#47">47</a>  <em> * order to use &lt;code>LargeSelect&lt;/code> you need to be willing to accept the</em>
<a name="48" href="#48">48</a>  <em> * fact that the result set may become inconsistent with the database if updates</em>
<a name="49" href="#49">49</a>  <em> * are processed subsequent to the queries being executed.  Specifying a memory</em>
<a name="50" href="#50">50</a>  <em> * page limit of 1 will give you a consistent view of the records but the totals</em>
<a name="51" href="#51">51</a>  <em> * may not be accurate and the performance will be terrible.  In most cases</em>
<a name="52" href="#52">52</a>  <em> * the potential for inconsistencies data should not cause any serious problems</em>
<a name="53" href="#53">53</a>  <em> * and performance should be pretty good (but read on for further warnings).</em>
<a name="54" href="#54">54</a>  <em> *</em>
<a name="55" href="#55">55</a>  <em> * &lt;p>The idea here is that the full query result would consume too much memory</em>
<a name="56" href="#56">56</a>  <em> * and if displayed to a user the page would be too long to be useful.  Rather</em>
<a name="57" href="#57">57</a>  <em> * than loading the full result set into memory, a window of data (the memory</em>
<a name="58" href="#58">58</a>  <em> * limit) is loaded and retrieved a page at a time.  If a request occurs for</em>
<a name="59" href="#59">59</a>  <em> * data that falls outside the currently loaded window of data then a new query</em>
<a name="60" href="#60">60</a>  <em> * is executed to fetch the required data.  Performance is optimized by</em>
<a name="61" href="#61">61</a>  <em> * starting a thread to execute the database query and fetch the results.  This</em>
<a name="62" href="#62">62</a>  <em> * will perform best when paging forwards through the data, but a minor</em>
<a name="63" href="#63">63</a>  <em> * optimization where the window is moved backwards by two rather than one page</em>
<a name="64" href="#64">64</a>  <em> * is included for when a user pages past the beginning of the window.</em>
<a name="65" href="#65">65</a>  <em> *</em>
<a name="66" href="#66">66</a>  <em> * &lt;p>As the query is performed in in steps, it is often the case that the total</em>
<a name="67" href="#67">67</a>  <em> * number of records and pages of data is unknown.  &lt;code>LargeSelect&lt;/code></em>
<a name="68" href="#68">68</a>  <em> * provides various methods for indicating how many records and pages it is</em>
<a name="69" href="#69">69</a>  <em> * currently aware of and for presenting this information to users.</em>
<a name="70" href="#70">70</a>  <em> *</em>
<a name="71" href="#71">71</a>  <em> * &lt;p>&lt;code>LargeSelect&lt;/code> utilises the &lt;code>Criteria&lt;/code> methods</em>
<a name="72" href="#72">72</a>  <em> * &lt;code>setOffset()&lt;/code> and &lt;code>setLimit()&lt;/code> to limit the amount of</em>
<a name="73" href="#73">73</a>  <em> * data retrieved from the database - these values are either passed through to</em>
<a name="74" href="#74">74</a>  <em> * the DBMS when supported (efficient with the caveat below) or handled by</em>
<a name="75" href="#75">75</a>  <em> * the Village API when it is not (not so efficient).  At time of writing</em>
<a name="76" href="#76">76</a>  <em> * &lt;code>Criteria&lt;/code> will only pass the offset and limit through to MySQL</em>
<a name="77" href="#77">77</a>  <em> * and PostgreSQL (with a few changes to &lt;code>DBOracle&lt;/code> and &lt;code></em>
<a name="78" href="#78">78</a>  <em> * BasePeer&lt;/code> Oracle support can be implemented by utilising the &lt;code></em>
<a name="79" href="#79">79</a>  <em> * rownum&lt;/code> pseudo column).</em>
<a name="80" href="#80">80</a>  <em> *</em>
<a name="81" href="#81">81</a>  <em> * &lt;p>As &lt;code>LargeSelect&lt;/code> must re-execute the query each time the user</em>
<a name="82" href="#82">82</a>  <em> * pages out of the window of loaded data, you should consider the impact of</em>
<a name="83" href="#83">83</a>  <em> * non-index sort orderings and other criteria that will require the DBMS to</em>
<a name="84" href="#84">84</a>  <em> * execute the entire query before filtering down to the offset and limit either</em>
<a name="85" href="#85">85</a>  <em> * internally or via Village.</em>
<a name="86" href="#86">86</a>  <em> *</em>
<a name="87" href="#87">87</a>  <em> * &lt;p>The memory limit defaults to 5 times the page size you specify, but</em>
<a name="88" href="#88">88</a>  <em> * alternative constructors and the class method &lt;code>setMemoryPageLimit()</em>
<a name="89" href="#89">89</a>  <em> * &lt;/code> allow you to override this for a specific instance of</em>
<a name="90" href="#90">90</a>  <em> * &lt;code>LargeSelect&lt;/code> or future instances respectively.</em>
<a name="91" href="#91">91</a>  <em> *</em>
<a name="92" href="#92">92</a>  <em> * &lt;p>Some of the constructors allow you to specify the name of the class to use</em>
<a name="93" href="#93">93</a>  <em> * to build the returnd rows.  This works by using reflection to find &lt;code></em>
<a name="94" href="#94">94</a>  <em> * addSelectColumns(Criteria)&lt;/code> and &lt;code>populateObjects(List)&lt;/code></em>
<a name="95" href="#95">95</a>  <em> * methods to add the necessary select columns to the criteria (only if it</em>
<a name="96" href="#96">96</a>  <em> * doesn't already contain any) and to convert query results from Village</em>
<a name="97" href="#97">97</a>  <em> * &lt;code>Record&lt;/code> objects to a class defined within the builder class.</em>
<a name="98" href="#98">98</a>  <em> * This allows you to use any of the Torque generated Peer classes, but also</em>
<a name="99" href="#99">99</a>  <em> * makes it fairly simple to construct business object classes that can be used</em>
<a name="100" href="#100">100</a> <em> * for this purpose (simply copy and customise the &lt;code>addSelectColumns()</em>
<a name="101" href="#101">101</a> <em> * &lt;/code>, &lt;code>populateObjects()&lt;/code>, &lt;code>row2Object()&lt;/code> and &lt;code></em>
<a name="102" href="#102">102</a> <em> * populateObject()&lt;/code> methods from an existing Peer class).</em>
<a name="103" href="#103">103</a> <em> *</em>
<a name="104" href="#104">104</a> <em> * &lt;p>Typically you will create a &lt;code>LargeSelect&lt;/code> using your &lt;code></em>
<a name="105" href="#105">105</a> <em> * Criteria&lt;/code> (perhaps created from the results of a search parameter</em>
<a name="106" href="#106">106</a> <em> * page), page size, memory page limit and return class name (for which you may</em>
<a name="107" href="#107">107</a> <em> * have defined a business object class before hand) and place this in user.Temp</em>
<a name="108" href="#108">108</a> <em> * thus:</em>
<a name="109" href="#109">109</a> <em> *</em>
<a name="110" href="#110">110</a> <em> * &lt;pre></em>
<a name="111" href="#111">111</a> <em> *     data.getUser().setTemp("someName", largeSelect);</em>
<a name="112" href="#112">112</a> <em> * &lt;/pre></em>
<a name="113" href="#113">113</a> <em> *</em>
<a name="114" href="#114">114</a> <em> * &lt;p>In your template you will then use something along the lines of:</em>
<a name="115" href="#115">115</a> <em> *</em>
<a name="116" href="#116">116</a> <em> * &lt;pre></em>
<a name="117" href="#117">117</a> <em> *    #set($largeSelect = $data.User.getTemp("someName"))</em>
<a name="118" href="#118">118</a> <em> *    #set($searchop = $data.Parameters.getString("searchop"))</em>
<a name="119" href="#119">119</a> <em> *    #if($searchop.equals("prev"))</em>
<a name="120" href="#120">120</a> <em> *      #set($recs = $largeSelect.PreviousResults)</em>
<a name="121" href="#121">121</a> <em> *    #else</em>
<a name="122" href="#122">122</a> <em> *      #if($searchop.equals("goto"))</em>
<a name="123" href="#123">123</a> <em> *        #set($recs = $largeSelect.getPage($data.Parameters.getInt("page", 1)))</em>
<a name="124" href="#124">124</a> <em> *      #else</em>
<a name="125" href="#125">125</a> <em> *        #set($recs = $largeSelect.NextResults)</em>
<a name="126" href="#126">126</a> <em> *      #end</em>
<a name="127" href="#127">127</a> <em> *    #end</em>
<a name="128" href="#128">128</a> <em> * &lt;/pre></em>
<a name="129" href="#129">129</a> <em> *</em>
<a name="130" href="#130">130</a> <em> * &lt;p>...to move through the records.  &lt;code>LargeSelect&lt;/code> implements a</em>
<a name="131" href="#131">131</a> <em> * number of convenience methods that make it easy to add all of the necessary</em>
<a name="132" href="#132">132</a> <em> * bells and whistles to your template.</em>
<a name="133" href="#133">133</a> <em> *</em>
<a name="134" href="#134">134</a> <em> * @author &lt;a href="<a href="mailto:john.mcnally@clearink.com" target="alexandria_uri">mailto:john.mcnally@clearink.com</a>">John D. McNally&lt;/a></em>
<a name="135" href="#135">135</a> <em> * @author &lt;a href="<a href="mailto:seade@backstagetech.com.au" target="alexandria_uri">mailto:seade@backstagetech.com.au</a>">Scott Eade&lt;/a></em>
<a name="136" href="#136">136</a> <em> * @version $Id: LargeSelect.java 534001 2007-05-01 10:46:05Z tv $</em>
<a name="137" href="#137">137</a> <em> */</em>
<a name="138" href="#138">138</a> <strong>public</strong> <strong>class</strong> <a href="../../../../org/apache/torque/util/LargeSelect.html">LargeSelect</a> implements Runnable, Serializable
<a name="139" href="#139">139</a> {
<a name="140" href="#140">140</a>     <em>/**<em>* Serial version */</em></em>
<a name="141" href="#141">141</a>     <strong>private</strong> <strong>static</strong> <strong>final</strong> <strong>long</strong> serialVersionUID = -1166842932571491942L;
<a name="142" href="#142">142</a> 
<a name="143" href="#143">143</a>     <em>/**<em>* The number of records that a page consists of.  */</em></em>
<a name="144" href="#144">144</a>     <strong>private</strong> <strong>int</strong> pageSize;
<a name="145" href="#145">145</a>     <em>/**<em>* The maximum number of records to maintain in memory. */</em></em>
<a name="146" href="#146">146</a>     <strong>private</strong> <strong>int</strong> memoryLimit;
<a name="147" href="#147">147</a> 
<a name="148" href="#148">148</a>     <em>/**<em>* The record number of the first record in memory. */</em></em>
<a name="149" href="#149">149</a>     <strong>private</strong> <strong>transient</strong> <strong>int</strong> blockBegin = 0;
<a name="150" href="#150">150</a>     <em>/**<em>* The record number of the last record in memory. */</em></em>
<a name="151" href="#151">151</a>     <strong>private</strong> <strong>transient</strong> <strong>int</strong> blockEnd;
<a name="152" href="#152">152</a>     <em>/**<em>* How much of the memory block is currently occupied with result data. */</em></em>
<a name="153" href="#153">153</a>     <strong>private</strong> <strong>volatile</strong> <strong>int</strong> currentlyFilledTo = -1;
<a name="154" href="#154">154</a> 
<a name="155" href="#155">155</a>     <em>/**<em>* The SQL query that this &lt;code>LargeSelect&lt;/code> represents. */</em></em>
<a name="156" href="#156">156</a>     <strong>private</strong> String query;
<a name="157" href="#157">157</a>     <em>/**<em>* The database name to get from Torque. */</em></em>
<a name="158" href="#158">158</a>     <strong>private</strong> String dbName;
<a name="159" href="#159">159</a> 
<a name="160" href="#160">160</a>     <em>/**<em>* The memory store of records. */</em></em>
<a name="161" href="#161">161</a>     <strong>private</strong> <strong>transient</strong> List results = <strong>null</strong>;
<a name="162" href="#162">162</a> 
<a name="163" href="#163">163</a>     <em>/**<em>* The thread that executes the query. */</em></em>
<a name="164" href="#164">164</a>     <strong>private</strong> <strong>transient</strong> Thread thread = <strong>null</strong>;
<a name="165" href="#165">165</a>     <em>/**<em>*</em></em>
<a name="166" href="#166">166</a> <em>     * A flag used to kill the thread when the currently executing query is no</em>
<a name="167" href="#167">167</a> <em>     * longer required.</em>
<a name="168" href="#168">168</a> <em>     */</em>
<a name="169" href="#169">169</a>     <strong>private</strong> <strong>transient</strong> <strong>volatile</strong> <strong>boolean</strong> killThread = false;
<a name="170" href="#170">170</a>     <em>/**<em>* A flag that indicates whether or not the query thread is running. */</em></em>
<a name="171" href="#171">171</a>     <strong>private</strong> <strong>transient</strong> <strong>volatile</strong> <strong>boolean</strong> threadRunning = false;
<a name="172" href="#172">172</a>     <em>/**<em>*</em></em>
<a name="173" href="#173">173</a> <em>     * An indication of whether or not the current query has completed</em>
<a name="174" href="#174">174</a> <em>     * processing.</em>
<a name="175" href="#175">175</a> <em>     */</em>
<a name="176" href="#176">176</a>     <strong>private</strong> <strong>transient</strong> <strong>volatile</strong> <strong>boolean</strong> queryCompleted = false;
<a name="177" href="#177">177</a>     <em>/**<em>*</em></em>
<a name="178" href="#178">178</a> <em>     * An indication of whether or not the totals (records and pages) are at</em>
<a name="179" href="#179">179</a> <em>     * their final values.</em>
<a name="180" href="#180">180</a> <em>     */</em>
<a name="181" href="#181">181</a>     <strong>private</strong> <strong>transient</strong> <strong>boolean</strong> totalsFinalized = false;
<a name="182" href="#182">182</a> 
<a name="183" href="#183">183</a>     <em>/**<em>* The cursor position in the result set. */</em></em>
<a name="184" href="#184">184</a>     <strong>private</strong> <strong>int</strong> position;
<a name="185" href="#185">185</a>     <em>/**<em>* The total number of pages known to exist. */</em></em>
<a name="186" href="#186">186</a>     <strong>private</strong> <strong>int</strong> totalPages = -1;
<a name="187" href="#187">187</a>     <em>/**<em>* The total number of records known to exist. */</em></em>
<a name="188" href="#188">188</a>     <strong>private</strong> <strong>int</strong> totalRecords = 0;
<a name="189" href="#189">189</a> 
<a name="190" href="#190">190</a>     <em>/**<em>* The criteria used for the query. */</em></em>
<a name="191" href="#191">191</a>     <strong>private</strong> <a href="../../../../org/apache/torque/util/Criteria.html">Criteria</a> criteria = <strong>null</strong>;
<a name="192" href="#192">192</a>     <em>/**<em>* The last page of results that were returned. */</em></em>
<a name="193" href="#193">193</a>     <strong>private</strong> <strong>transient</strong> List lastResults;
<a name="194" href="#194">194</a> 
<a name="195" href="#195">195</a>     <em>/**<em>*</em></em>
<a name="196" href="#196">196</a> <em>     * The class that is possibly used to construct the criteria and used</em>
<a name="197" href="#197">197</a> <em>     * to transform the Village Records into the desired OM or business objects.</em>
<a name="198" href="#198">198</a> <em>     */</em>
<a name="199" href="#199">199</a>     <strong>private</strong> Class returnBuilderClass = <strong>null</strong>;
<a name="200" href="#200">200</a>     <em>/**<em>*</em></em>
<a name="201" href="#201">201</a> <em>     * A reference to the method in the return builder class that will</em>
<a name="202" href="#202">202</a> <em>     * convert the Village Records to the desired class.</em>
<a name="203" href="#203">203</a> <em>     */</em>
<a name="204" href="#204">204</a>     <strong>private</strong> <strong>transient</strong> Method populateObjectsMethod = <strong>null</strong>;
<a name="205" href="#205">205</a> 
<a name="206" href="#206">206</a>     <em>/**<em>*</em></em>
<a name="207" href="#207">207</a> <em>     * The default value ("&amp;gt;") used to indicate that the total number of</em>
<a name="208" href="#208">208</a> <em>     * records or pages is unknown.</em>
<a name="209" href="#209">209</a> <em>     */</em>
<a name="210" href="#210">210</a>     <strong>public</strong> <strong>static</strong> <strong>final</strong> String DEFAULT_MORE_INDICATOR = <span class="string">"&amp;gt;"</span>;
<a name="211" href="#211">211</a> 
<a name="212" href="#212">212</a>     <em>/**<em>*</em></em>
<a name="213" href="#213">213</a> <em>     * The value used to indicate that the total number of records or pages is</em>
<a name="214" href="#214">214</a> <em>     * unknown (default: "&amp;gt;"). You can use &lt;code>setMoreIndicator()&lt;/code></em>
<a name="215" href="#215">215</a> <em>     * to change this to whatever value you like (e.g. "more than").</em>
<a name="216" href="#216">216</a> <em>     */</em>
<a name="217" href="#217">217</a>     <strong>private</strong> <strong>static</strong> String moreIndicator = DEFAULT_MORE_INDICATOR;
<a name="218" href="#218">218</a> 
<a name="219" href="#219">219</a>     <em>/**<em>*</em></em>
<a name="220" href="#220">220</a> <em>     * The default value for the maximum number of pages of data to be retained</em>
<a name="221" href="#221">221</a> <em>     * in memory.</em>
<a name="222" href="#222">222</a> <em>     */</em>
<a name="223" href="#223">223</a>     <strong>public</strong> <strong>static</strong> <strong>final</strong> <strong>int</strong> DEFAULT_MEMORY_LIMIT_PAGES = 5;
<a name="224" href="#224">224</a> 
<a name="225" href="#225">225</a>     <em>/**<em>*</em></em>
<a name="226" href="#226">226</a> <em>     * The maximum number of pages of data to be retained in memory.  Use</em>
<a name="227" href="#227">227</a> <em>     * &lt;code>setMemoryPageLimit()&lt;/code> to provide your own value.</em>
<a name="228" href="#228">228</a> <em>     */</em>
<a name="229" href="#229">229</a>     <strong>private</strong> <strong>static</strong> <strong>int</strong> memoryPageLimit = DEFAULT_MEMORY_LIMIT_PAGES;
<a name="230" href="#230">230</a> 
<a name="231" href="#231">231</a>     <em>/**<em>*</em></em>
<a name="232" href="#232">232</a> <em>     * The number of milliseconds to sleep when the result of a query</em>
<a name="233" href="#233">233</a> <em>     * is not yet available.</em>
<a name="234" href="#234">234</a> <em>     */</em>
<a name="235" href="#235">235</a>     <strong>private</strong> <strong>static</strong> <strong>final</strong> <strong>int</strong> QUERY_NOT_COMPLETED_SLEEP_TIME = 500;
<a name="236" href="#236">236</a> 
<a name="237" href="#237">237</a>     <em>/**<em>*</em></em>
<a name="238" href="#238">238</a> <em>     * The number of milliseconds to sleep before retrying to stop a query.</em>
<a name="239" href="#239">239</a> <em>     */</em>
<a name="240" href="#240">240</a>     <strong>private</strong> <strong>static</strong> <strong>final</strong> <strong>int</strong> QUERY_STOP_SLEEP_TIME = 100;
<a name="241" href="#241">241</a> 
<a name="242" href="#242">242</a>     <em>/**<em>* A place to store search parameters that relate to this query. */</em></em>
<a name="243" href="#243">243</a>     <strong>private</strong> Hashtable params = <strong>null</strong>;
<a name="244" href="#244">244</a> 
<a name="245" href="#245">245</a>     <em>/**<em>* Logging */</em></em>
<a name="246" href="#246">246</a>     <strong>private</strong> <strong>static</strong> Log log = LogFactory.getLog(LargeSelect.<strong>class</strong>);
<a name="247" href="#247">247</a> 
<a name="248" href="#248">248</a>     <em>/**<em>*</em></em>
<a name="249" href="#249">249</a> <em>     * Creates a LargeSelect whose results are returned as a &lt;code>List&lt;/code></em>
<a name="250" href="#250">250</a> <em>     * containing a maximum of &lt;code>pageSize&lt;/code> Village &lt;code>Record&lt;/code></em>
<a name="251" href="#251">251</a> <em>     * objects at a time, maintaining a maximum of</em>
<a name="252" href="#252">252</a> <em>     * &lt;code>LargeSelect.memoryPageLimit&lt;/code> pages of results in memory.</em>
<a name="253" href="#253">253</a> <em>     *</em>
<a name="254" href="#254">254</a> <em>     * @param criteria object used by BasePeer to build the query.  In order to</em>
<a name="255" href="#255">255</a> <em>     * allow this class to utilise database server implemented offsets and</em>
<a name="256" href="#256">256</a> <em>     * limits (when available), the provided criteria must not have any limit or</em>
<a name="257" href="#257">257</a> <em>     * offset defined.</em>
<a name="258" href="#258">258</a> <em>     * @param pageSize number of rows to return in one block.</em>
<a name="259" href="#259">259</a> <em>     * @throws IllegalArgumentException if &lt;code>criteria&lt;/code> uses one or</em>
<a name="260" href="#260">260</a> <em>     * both of offset and limit, or if &lt;code>pageSize&lt;/code> is less than 1;</em>
<a name="261" href="#261">261</a> <em>     */</em>
<a name="262" href="#262">262</a>     <strong>public</strong> <a href="../../../../org/apache/torque/util/LargeSelect.html">LargeSelect</a>(<a href="../../../../org/apache/torque/util/Criteria.html">Criteria</a> criteria, <strong>int</strong> pageSize)
<a name="263" href="#263">263</a>     {
<a name="264" href="#264">264</a>         <strong>this</strong>(criteria, pageSize, LargeSelect.memoryPageLimit);
<a name="265" href="#265">265</a>     }
<a name="266" href="#266">266</a> 
<a name="267" href="#267">267</a>     <em>/**<em>*</em></em>
<a name="268" href="#268">268</a> <em>     * Creates a LargeSelect whose results are returned as a &lt;code>List&lt;/code></em>
<a name="269" href="#269">269</a> <em>     * containing a maximum of &lt;code>pageSize&lt;/code> Village &lt;code>Record&lt;/code></em>
<a name="270" href="#270">270</a> <em>     * objects at a time, maintaining a maximum of &lt;code>memoryPageLimit&lt;/code></em>
<a name="271" href="#271">271</a> <em>     * pages of results in memory.</em>
<a name="272" href="#272">272</a> <em>     *</em>
<a name="273" href="#273">273</a> <em>     * @param criteria object used by BasePeer to build the query.  In order to</em>
<a name="274" href="#274">274</a> <em>     * allow this class to utilise database server implemented offsets and</em>
<a name="275" href="#275">275</a> <em>     * limits (when available), the provided criteria must not have any limit or</em>
<a name="276" href="#276">276</a> <em>     * offset defined.</em>
<a name="277" href="#277">277</a> <em>     * @param pageSize number of rows to return in one block.</em>
<a name="278" href="#278">278</a> <em>     * @param memoryPageLimit maximum number of pages worth of rows to be held</em>
<a name="279" href="#279">279</a> <em>     * in memory at one time.</em>
<a name="280" href="#280">280</a> <em>     * @throws IllegalArgumentException if &lt;code>criteria&lt;/code> uses one or</em>
<a name="281" href="#281">281</a> <em>     * both of offset and limit, or if &lt;code>pageSize&lt;/code> or</em>
<a name="282" href="#282">282</a> <em>     * &lt;code>memoryLimitPages&lt;/code> are less than 1;</em>
<a name="283" href="#283">283</a> <em>     */</em>
<a name="284" href="#284">284</a>     <strong>public</strong> <a href="../../../../org/apache/torque/util/LargeSelect.html">LargeSelect</a>(<a href="../../../../org/apache/torque/util/Criteria.html">Criteria</a> criteria, <strong>int</strong> pageSize, <strong>int</strong> memoryPageLimit)
<a name="285" href="#285">285</a>     {
<a name="286" href="#286">286</a>         init(criteria, pageSize, memoryPageLimit);
<a name="287" href="#287">287</a>     }
<a name="288" href="#288">288</a> 
<a name="289" href="#289">289</a>     <em>/**<em>*</em></em>
<a name="290" href="#290">290</a> <em>     * Creates a LargeSelect whose results are returned as a &lt;code>List&lt;/code></em>
<a name="291" href="#291">291</a> <em>     * containing a maximum of &lt;code>pageSize&lt;/code> objects of the type</em>
<a name="292" href="#292">292</a> <em>     * defined within the class named &lt;code>returnBuilderClassName&lt;/code> at a</em>
<a name="293" href="#293">293</a> <em>     * time, maintaining a maximum of &lt;code>LargeSelect.memoryPageLimit&lt;/code></em>
<a name="294" href="#294">294</a> <em>     * pages of results in memory.</em>
<a name="295" href="#295">295</a> <em>     *</em>
<a name="296" href="#296">296</a> <em>     * @param criteria object used by BasePeer to build the query.  In order to</em>
<a name="297" href="#297">297</a> <em>     * allow this class to utilise database server implemented offsets and</em>
<a name="298" href="#298">298</a> <em>     * limits (when available), the provided criteria must not have any limit or</em>
<a name="299" href="#299">299</a> <em>     * offset defined.  If the criteria does not include the definition of any</em>
<a name="300" href="#300">300</a> <em>     * select columns the &lt;code>addSelectColumns(Criteria)&lt;/code> method of</em>
<a name="301" href="#301">301</a> <em>     * the class named as &lt;code>returnBuilderClassName&lt;/code> will be used to</em>
<a name="302" href="#302">302</a> <em>     * add them.</em>
<a name="303" href="#303">303</a> <em>     * @param pageSize number of rows to return in one block.</em>
<a name="304" href="#304">304</a> <em>     * @param returnBuilderClassName The name of the class that will be used to</em>
<a name="305" href="#305">305</a> <em>     * build the result records (may implement &lt;code>addSelectColumns(Criteria)</em>
<a name="306" href="#306">306</a> <em>     * &lt;/code> and must implement &lt;code>populateObjects(List)&lt;/code>).</em>
<a name="307" href="#307">307</a> <em>     * @throws IllegalArgumentException if &lt;code>criteria&lt;/code> uses one or</em>
<a name="308" href="#308">308</a> <em>     * both of offset and limit, if &lt;code>pageSize&lt;/code> is less than 1, or if</em>
<a name="309" href="#309">309</a> <em>     * problems are experienced locating and invoking either one or both of</em>
<a name="310" href="#310">310</a> <em>     * &lt;code>addSelectColumns(Criteria)&lt;/code> and &lt;code> populateObjects(List)</em>
<a name="311" href="#311">311</a> <em>     * &lt;/code> in the class named &lt;code>returnBuilderClassName&lt;/code>.</em>
<a name="312" href="#312">312</a> <em>     */</em>
<a name="313" href="#313">313</a>     <strong>public</strong> <a href="../../../../org/apache/torque/util/LargeSelect.html">LargeSelect</a>(
<a name="314" href="#314">314</a>             <a href="../../../../org/apache/torque/util/Criteria.html">Criteria</a> criteria,
<a name="315" href="#315">315</a>             <strong>int</strong> pageSize,
<a name="316" href="#316">316</a>             String returnBuilderClassName)
<a name="317" href="#317">317</a>     {
<a name="318" href="#318">318</a>         <strong>this</strong>(
<a name="319" href="#319">319</a>             criteria,
<a name="320" href="#320">320</a>             pageSize,
<a name="321" href="#321">321</a>             LargeSelect.memoryPageLimit,
<a name="322" href="#322">322</a>             returnBuilderClassName);
<a name="323" href="#323">323</a>     }
<a name="324" href="#324">324</a> 
<a name="325" href="#325">325</a>     <em>/**<em>*</em></em>
<a name="326" href="#326">326</a> <em>     * Creates a LargeSelect whose results are returned as a &lt;code>List&lt;/code></em>
<a name="327" href="#327">327</a> <em>     * containing a maximum of &lt;code>pageSize&lt;/code> objects of the type</em>
<a name="328" href="#328">328</a> <em>     * defined within the class named &lt;code>returnBuilderClassName&lt;/code> at a</em>
<a name="329" href="#329">329</a> <em>     * time, maintaining a maximum of &lt;code>memoryPageLimit&lt;/code> pages of</em>
<a name="330" href="#330">330</a> <em>     * results in memory.</em>
<a name="331" href="#331">331</a> <em>     *</em>
<a name="332" href="#332">332</a> <em>     * @param criteria object used by BasePeer to build the query.  In order to</em>
<a name="333" href="#333">333</a> <em>     * allow this class to utilise database server implemented offsets and</em>
<a name="334" href="#334">334</a> <em>     * limits (when available), the provided criteria must not have any limit or</em>
<a name="335" href="#335">335</a> <em>     * offset defined.  If the criteria does not include the definition of any</em>
<a name="336" href="#336">336</a> <em>     * select columns the &lt;code>addSelectColumns(Criteria)&lt;/code> method of</em>
<a name="337" href="#337">337</a> <em>     * the class named as &lt;code>returnBuilderClassName&lt;/code> will be used to</em>
<a name="338" href="#338">338</a> <em>     * add them.</em>
<a name="339" href="#339">339</a> <em>     * @param pageSize number of rows to return in one block.</em>
<a name="340" href="#340">340</a> <em>     * @param memoryPageLimit maximum number of pages worth of rows to be held</em>
<a name="341" href="#341">341</a> <em>     * in memory at one time.</em>
<a name="342" href="#342">342</a> <em>     * @param returnBuilderClassName The name of the class that will be used to</em>
<a name="343" href="#343">343</a> <em>     * build the result records (may implement &lt;code>addSelectColumns(Criteria)</em>
<a name="344" href="#344">344</a> <em>     * &lt;/code> and must implement &lt;code>populateObjects(List)&lt;/code>).</em>
<a name="345" href="#345">345</a> <em>     * @throws IllegalArgumentException if &lt;code>criteria&lt;/code> uses one or</em>
<a name="346" href="#346">346</a> <em>     * both of offset and limit, if &lt;code>pageSize&lt;/code> or &lt;code></em>
<a name="347" href="#347">347</a> <em>     * memoryLimitPages&lt;/code> are less than 1, or if problems are experienced</em>
<a name="348" href="#348">348</a> <em>     * locating and invoking either one or both of &lt;code></em>
<a name="349" href="#349">349</a> <em>     * addSelectColumns(Criteria)&lt;/code> and &lt;code> populateObjects(List)&lt;/code></em>
<a name="350" href="#350">350</a> <em>     * in the class named &lt;code>returnBuilderClassName&lt;/code>.</em>
<a name="351" href="#351">351</a> <em>     */</em>
<a name="352" href="#352">352</a>     <strong>public</strong> <a href="../../../../org/apache/torque/util/LargeSelect.html">LargeSelect</a>(
<a name="353" href="#353">353</a>             <a href="../../../../org/apache/torque/util/Criteria.html">Criteria</a> criteria,
<a name="354" href="#354">354</a>             <strong>int</strong> pageSize,
<a name="355" href="#355">355</a>             <strong>int</strong> memoryPageLimit,
<a name="356" href="#356">356</a>             String returnBuilderClassName)
<a name="357" href="#357">357</a>     {
<a name="358" href="#358">358</a>         <strong>try</strong>
<a name="359" href="#359">359</a>         {
<a name="360" href="#360">360</a>             <strong>this</strong>.returnBuilderClass = Class.forName(returnBuilderClassName);
<a name="361" href="#361">361</a> 
<a name="362" href="#362">362</a>             <em class="comment">// Add the select columns if necessary.</em>
<a name="363" href="#363">363</a>             <strong>if</strong> (criteria.getSelectColumns().size() == 0)
<a name="364" href="#364">364</a>             {
<a name="365" href="#365">365</a>                 Class[] argTypes = { Criteria.<strong>class</strong> };
<a name="366" href="#366">366</a>                 Method selectColumnAdder =
<a name="367" href="#367">367</a>                     returnBuilderClass.getMethod(<span class="string">"addSelectColumns"</span>, argTypes);
<a name="368" href="#368">368</a>                 Object[] theArgs = { criteria };
<a name="369" href="#369">369</a>                 selectColumnAdder.invoke(returnBuilderClass.newInstance(),
<a name="370" href="#370">370</a>                         theArgs);
<a name="371" href="#371">371</a>             }
<a name="372" href="#372">372</a>         }
<a name="373" href="#373">373</a>         <strong>catch</strong> (Exception e)
<a name="374" href="#374">374</a>         {
<a name="375" href="#375">375</a>             <strong>throw</strong> <strong>new</strong> IllegalArgumentException(
<a name="376" href="#376">376</a>                     <span class="string">"The class named as returnBuilderClassName does not "</span>
<a name="377" href="#377">377</a>                     + <span class="string">"provide the necessary facilities - see javadoc."</span>);
<a name="378" href="#378">378</a>         }
<a name="379" href="#379">379</a> 
<a name="380" href="#380">380</a>         init(criteria, pageSize, memoryPageLimit);
<a name="381" href="#381">381</a>     }
<a name="382" href="#382">382</a> 
<a name="383" href="#383">383</a>     <em>/**<em>*</em></em>
<a name="384" href="#384">384</a> <em>     * Access the populateObjects method.</em>
<a name="385" href="#385">385</a> <em>     *</em>
<a name="386" href="#386">386</a> <em>     * @throws SecurityException if the security manager does not allow</em>
<a name="387" href="#387">387</a> <em>     *         access to the method.</em>
<a name="388" href="#388">388</a> <em>     * @throws NoSuchMethodException if the poulateObjects method does not</em>
<a name="389" href="#389">389</a> <em>     *         exist.</em>
<a name="390" href="#390">390</a> <em>     */</em>
<a name="391" href="#391">391</a>     <strong>private</strong> Method getPopulateObjectsMethod()
<a name="392" href="#392">392</a>             throws NoSuchMethodException
<a name="393" href="#393">393</a>     {
<a name="394" href="#394">394</a>         <strong>if</strong> (<strong>null</strong> == populateObjectsMethod)
<a name="395" href="#395">395</a>         {
<a name="396" href="#396">396</a>             Class[] argTypes = { List.<strong>class</strong> };
<a name="397" href="#397">397</a>             populateObjectsMethod
<a name="398" href="#398">398</a>                     = returnBuilderClass.getMethod(<span class="string">"populateObjects"</span>, argTypes);
<a name="399" href="#399">399</a>         }
<a name="400" href="#400">400</a>         <strong>return</strong> populateObjectsMethod;
<a name="401" href="#401">401</a>     }
<a name="402" href="#402">402</a> 
<a name="403" href="#403">403</a>     <em>/**<em>*</em></em>
<a name="404" href="#404">404</a> <em>     * Called by the constructors to start the query.</em>
<a name="405" href="#405">405</a> <em>     *</em>
<a name="406" href="#406">406</a> <em>     * @param criteria Object used by &lt;code>BasePeer&lt;/code> to build the query.</em>
<a name="407" href="#407">407</a> <em>     * In order to allow this class to utilise database server implemented</em>
<a name="408" href="#408">408</a> <em>     * offsets and limits (when available), the provided criteria must not have</em>
<a name="409" href="#409">409</a> <em>     * any limit or offset defined.</em>
<a name="410" href="#410">410</a> <em>     * @param pageSize number of rows to return in one block.</em>
<a name="411" href="#411">411</a> <em>     * @param memoryLimitPages maximum number of pages worth of rows to be held</em>
<a name="412" href="#412">412</a> <em>     * in memory at one time.</em>
<a name="413" href="#413">413</a> <em>     * @throws IllegalArgumentException if &lt;code>criteria&lt;/code> uses one or</em>
<a name="414" href="#414">414</a> <em>     * both of offset and limit and if &lt;code>pageSize&lt;/code> or</em>
<a name="415" href="#415">415</a> <em>     * &lt;code>memoryLimitPages&lt;/code> are less than 1;</em>
<a name="416" href="#416">416</a> <em>     */</em>
<a name="417" href="#417">417</a>     <strong>private</strong> <strong>void</strong> init(<a href="../../../../org/apache/torque/util/Criteria.html">Criteria</a> criteria, <strong>int</strong> pageSize, <strong>int</strong> memoryLimitPages)
<a name="418" href="#418">418</a>     {
<a name="419" href="#419">419</a>         <strong>if</strong> (criteria.getOffset() != 0 || criteria.getLimit() != -1)
<a name="420" href="#420">420</a>         {
<a name="421" href="#421">421</a>             <strong>throw</strong> <strong>new</strong> IllegalArgumentException(
<a name="422" href="#422">422</a>                     <span class="string">"criteria must not use Offset and/or Limit."</span>);
<a name="423" href="#423">423</a>         }
<a name="424" href="#424">424</a> 
<a name="425" href="#425">425</a>         <strong>if</strong> (pageSize &lt; 1)
<a name="426" href="#426">426</a>         {
<a name="427" href="#427">427</a>             <strong>throw</strong> <strong>new</strong> IllegalArgumentException(
<a name="428" href="#428">428</a>                     <span class="string">"pageSize must be greater than zero."</span>);
<a name="429" href="#429">429</a>         }
<a name="430" href="#430">430</a> 
<a name="431" href="#431">431</a>         <strong>if</strong> (memoryLimitPages &lt; 1)
<a name="432" href="#432">432</a>         {
<a name="433" href="#433">433</a>             <strong>throw</strong> <strong>new</strong> IllegalArgumentException(
<a name="434" href="#434">434</a>                     <span class="string">"memoryPageLimit must be greater than zero."</span>);
<a name="435" href="#435">435</a>         }
<a name="436" href="#436">436</a> 
<a name="437" href="#437">437</a>         <strong>this</strong>.pageSize = pageSize;
<a name="438" href="#438">438</a>         <strong>this</strong>.memoryLimit = pageSize * memoryLimitPages;
<a name="439" href="#439">439</a>         <strong>this</strong>.criteria = criteria;
<a name="440" href="#440">440</a>         dbName = criteria.getDbName();
<a name="441" href="#441">441</a>         blockEnd = blockBegin + memoryLimit - 1;
<a name="442" href="#442">442</a>         startQuery(pageSize);
<a name="443" href="#443">443</a>     }
<a name="444" href="#444">444</a> 
<a name="445" href="#445">445</a>     <em>/**<em>*</em></em>
<a name="446" href="#446">446</a> <em>     * Retrieve a specific page, if it exists.</em>
<a name="447" href="#447">447</a> <em>     *</em>
<a name="448" href="#448">448</a> <em>     * @param pageNumber the number of the page to be retrieved - must be</em>
<a name="449" href="#449">449</a> <em>     * greater than zero.  An empty &lt;code>List&lt;/code> will be returned if</em>
<a name="450" href="#450">450</a> <em>     * &lt;code>pageNumber&lt;/code> exceeds the total number of pages that exist.</em>
<a name="451" href="#451">451</a> <em>     * @return a &lt;code>List&lt;/code> of query results containing a maximum of</em>
<a name="452" href="#452">452</a> <em>     * &lt;code>pageSize&lt;/code> results.</em>
<a name="453" href="#453">453</a> <em>     * @throws IllegalArgumentException when &lt;code>pageNo&lt;/code> is not</em>
<a name="454" href="#454">454</a> <em>     * greater than zero.</em>
<a name="455" href="#455">455</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="456" href="#456">456</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="457" href="#457">457</a> <em>     */</em>
<a name="458" href="#458">458</a>     <strong>public</strong> List getPage(<strong>int</strong> pageNumber) throws TorqueException
<a name="459" href="#459">459</a>     {
<a name="460" href="#460">460</a>         <strong>if</strong> (pageNumber &lt; 1)
<a name="461" href="#461">461</a>         {
<a name="462" href="#462">462</a>             <strong>throw</strong> <strong>new</strong> IllegalArgumentException(
<a name="463" href="#463">463</a>                     <span class="string">"pageNumber must be greater than zero."</span>);
<a name="464" href="#464">464</a>         }
<a name="465" href="#465">465</a>         <strong>return</strong> getResults((pageNumber - 1) * pageSize);
<a name="466" href="#466">466</a>     }
<a name="467" href="#467">467</a> 
<a name="468" href="#468">468</a>     <em>/**<em>*</em></em>
<a name="469" href="#469">469</a> <em>     * Gets the next page of rows.</em>
<a name="470" href="#470">470</a> <em>     *</em>
<a name="471" href="#471">471</a> <em>     * @return a &lt;code>List&lt;/code> of query results containing a maximum of</em>
<a name="472" href="#472">472</a> <em>     * &lt;code>pageSize&lt;/code> reslts.</em>
<a name="473" href="#473">473</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="474" href="#474">474</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="475" href="#475">475</a> <em>     */</em>
<a name="476" href="#476">476</a>     <strong>public</strong> List getNextResults() throws TorqueException
<a name="477" href="#477">477</a>     {
<a name="478" href="#478">478</a>         <strong>if</strong> (!getNextResultsAvailable())
<a name="479" href="#479">479</a>         {
<a name="480" href="#480">480</a>             <strong>return</strong> getCurrentPageResults();
<a name="481" href="#481">481</a>         }
<a name="482" href="#482">482</a>         <strong>return</strong> getResults(position);
<a name="483" href="#483">483</a>     }
<a name="484" href="#484">484</a> 
<a name="485" href="#485">485</a>     <em>/**<em>*</em></em>
<a name="486" href="#486">486</a> <em>     * Provide access to the results from the current page.</em>
<a name="487" href="#487">487</a> <em>     *</em>
<a name="488" href="#488">488</a> <em>     * @return a &lt;code>List&lt;/code> of query results containing a maximum of</em>
<a name="489" href="#489">489</a> <em>     * &lt;code>pageSize&lt;/code> reslts.</em>
<a name="490" href="#490">490</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="491" href="#491">491</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="492" href="#492">492</a> <em>     */</em>
<a name="493" href="#493">493</a>     <strong>public</strong> List getCurrentPageResults() throws TorqueException
<a name="494" href="#494">494</a>     {
<a name="495" href="#495">495</a>         <strong>return</strong> <strong>null</strong> == lastResults &amp;&amp; position > 0
<a name="496" href="#496">496</a>                 ? getResults(position) : lastResults;
<a name="497" href="#497">497</a>     }
<a name="498" href="#498">498</a> 
<a name="499" href="#499">499</a>     <em>/**<em>*</em></em>
<a name="500" href="#500">500</a> <em>     * Gets the previous page of rows.</em>
<a name="501" href="#501">501</a> <em>     *</em>
<a name="502" href="#502">502</a> <em>     * @return a &lt;code>List&lt;/code> of query results containing a maximum of</em>
<a name="503" href="#503">503</a> <em>     * &lt;code>pageSize&lt;/code> reslts.</em>
<a name="504" href="#504">504</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="505" href="#505">505</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="506" href="#506">506</a> <em>     */</em>
<a name="507" href="#507">507</a>     <strong>public</strong> List getPreviousResults() throws TorqueException
<a name="508" href="#508">508</a>     {
<a name="509" href="#509">509</a>         <strong>if</strong> (!getPreviousResultsAvailable())
<a name="510" href="#510">510</a>         {
<a name="511" href="#511">511</a>             <strong>return</strong> getCurrentPageResults();
<a name="512" href="#512">512</a>         }
<a name="513" href="#513">513</a> 
<a name="514" href="#514">514</a>         <strong>int</strong> start;
<a name="515" href="#515">515</a>         <strong>if</strong> (position - 2 * pageSize &lt; 0)
<a name="516" href="#516">516</a>         {
<a name="517" href="#517">517</a>             start = 0;
<a name="518" href="#518">518</a>         }
<a name="519" href="#519">519</a>         <strong>else</strong>
<a name="520" href="#520">520</a>         {
<a name="521" href="#521">521</a>             start = position - 2 * pageSize;
<a name="522" href="#522">522</a>         }
<a name="523" href="#523">523</a>         <strong>return</strong> getResults(start);
<a name="524" href="#524">524</a>     }
<a name="525" href="#525">525</a> 
<a name="526" href="#526">526</a>     <em>/**<em>*</em></em>
<a name="527" href="#527">527</a> <em>     * Gets a page of rows starting at a specified row.</em>
<a name="528" href="#528">528</a> <em>     *</em>
<a name="529" href="#529">529</a> <em>     * @param start the starting row.</em>
<a name="530" href="#530">530</a> <em>     * @return a &lt;code>List&lt;/code> of query results containing a maximum of</em>
<a name="531" href="#531">531</a> <em>     * &lt;code>pageSize&lt;/code> reslts.</em>
<a name="532" href="#532">532</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="533" href="#533">533</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="534" href="#534">534</a> <em>     */</em>
<a name="535" href="#535">535</a>     <strong>private</strong> List getResults(<strong>int</strong> start) throws TorqueException
<a name="536" href="#536">536</a>     {
<a name="537" href="#537">537</a>         <strong>return</strong> getResults(start, pageSize);
<a name="538" href="#538">538</a>     }
<a name="539" href="#539">539</a> 
<a name="540" href="#540">540</a>     <em>/**<em>*</em></em>
<a name="541" href="#541">541</a> <em>     * Gets a block of rows starting at a specified row and containing a</em>
<a name="542" href="#542">542</a> <em>     * specified number of rows.</em>
<a name="543" href="#543">543</a> <em>     *</em>
<a name="544" href="#544">544</a> <em>     * @param start the starting row.</em>
<a name="545" href="#545">545</a> <em>     * @param size the number of rows.</em>
<a name="546" href="#546">546</a> <em>     * @return a &lt;code>List&lt;/code> of query results containing a maximum of</em>
<a name="547" href="#547">547</a> <em>     * &lt;code>pageSize&lt;/code> reslts.</em>
<a name="548" href="#548">548</a> <em>     * @throws IllegalArgumentException if &lt;code>size &amp;gt; memoryLimit&lt;/code> or</em>
<a name="549" href="#549">549</a> <em>     * &lt;code>start&lt;/code> and &lt;code>size&lt;/code> result in a situation that is</em>
<a name="550" href="#550">550</a> <em>     * not catered for.</em>
<a name="551" href="#551">551</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="552" href="#552">552</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="553" href="#553">553</a> <em>     */</em>
<a name="554" href="#554">554</a>     <strong>private</strong> <strong>synchronized</strong> List getResults(<strong>int</strong> start, <strong>int</strong> size)
<a name="555" href="#555">555</a>             throws <a href="../../../../org/apache/torque/TorqueException.html">TorqueException</a>
<a name="556" href="#556">556</a>     {
<a name="557" href="#557">557</a>         <strong>if</strong> (log.isDebugEnabled())
<a name="558" href="#558">558</a>         {
<a name="559" href="#559">559</a>             log.debug(<span class="string">"getResults(start: "</span> + start
<a name="560" href="#560">560</a>                     + <span class="string">", size: "</span> + size + <span class="string">") invoked."</span>);
<a name="561" href="#561">561</a>         }
<a name="562" href="#562">562</a> 
<a name="563" href="#563">563</a>         <strong>if</strong> (size > memoryLimit)
<a name="564" href="#564">564</a>         {
<a name="565" href="#565">565</a>             <strong>throw</strong> <strong>new</strong> IllegalArgumentException(<span class="string">"size ("</span> + size
<a name="566" href="#566">566</a>                     + <span class="string">") exceeds memory limit ("</span> + memoryLimit + <span class="string">")."</span>);
<a name="567" href="#567">567</a>         }
<a name="568" href="#568">568</a> 
<a name="569" href="#569">569</a>         <em class="comment">// Request was for a block of rows which should be in progess.</em>
<a name="570" href="#570">570</a>         <em class="comment">// If the rows have not yet been returned, wait for them to be</em>
<a name="571" href="#571">571</a>         <em class="comment">// retrieved.</em>
<a name="572" href="#572">572</a>         <strong>if</strong> (start >= blockBegin &amp;&amp; (start + size - 1) &lt;= blockEnd)
<a name="573" href="#573">573</a>         {
<a name="574" href="#574">574</a>             <strong>if</strong> (log.isDebugEnabled())
<a name="575" href="#575">575</a>             {
<a name="576" href="#576">576</a>                 log.debug(<span class="string">"getResults(): Sleeping until "</span>
<a name="577" href="#577">577</a>                         + <span class="string">"start+size-1 ("</span> + (start + size - 1)
<a name="578" href="#578">578</a>                         + <span class="string">") > currentlyFilledTo ("</span> + currentlyFilledTo
<a name="579" href="#579">579</a>                         + <span class="string">") &amp;&amp; !queryCompleted (!"</span> + queryCompleted + <span class="string">")"</span>);
<a name="580" href="#580">580</a>             }
<a name="581" href="#581">581</a>             <strong>while</strong> (((start + size - 1) > currentlyFilledTo) &amp;&amp; !queryCompleted)
<a name="582" href="#582">582</a>             {
<a name="583" href="#583">583</a>                 <strong>try</strong>
<a name="584" href="#584">584</a>                 {
<a name="585" href="#585">585</a>                     Thread.sleep(QUERY_NOT_COMPLETED_SLEEP_TIME);
<a name="586" href="#586">586</a>                 }
<a name="587" href="#587">587</a>                 <strong>catch</strong> (InterruptedException e)
<a name="588" href="#588">588</a>                 {
<a name="589" href="#589">589</a>                     <strong>throw</strong> <strong>new</strong> <a href="../../../../org/apache/torque/TorqueException.html">TorqueException</a>(<span class="string">"Unexpected interruption"</span>, e);
<a name="590" href="#590">590</a>                 }
<a name="591" href="#591">591</a>             }
<a name="592" href="#592">592</a>         }
<a name="593" href="#593">593</a> 
<a name="594" href="#594">594</a>         <em class="comment">// Going in reverse direction, trying to limit db hits so assume user</em>
<a name="595" href="#595">595</a>         <em class="comment">// might want at least 2 sets of data.</em>
<a name="596" href="#596">596</a>         <strong>else</strong> <strong>if</strong> (start &lt; blockBegin &amp;&amp; start >= 0)
<a name="597" href="#597">597</a>         {
<a name="598" href="#598">598</a>             <strong>if</strong> (log.isDebugEnabled())
<a name="599" href="#599">599</a>             {
<a name="600" href="#600">600</a>                 log.debug(<span class="string">"getResults(): Paging backwards as start ("</span> + start
<a name="601" href="#601">601</a>                         + <span class="string">") &lt; blockBegin ("</span> + blockBegin + <span class="string">") &amp;&amp; start >= 0"</span>);
<a name="602" href="#602">602</a>             }
<a name="603" href="#603">603</a>             stopQuery();
<a name="604" href="#604">604</a>             <strong>if</strong> (memoryLimit >= 2 * size)
<a name="605" href="#605">605</a>             {
<a name="606" href="#606">606</a>                 blockBegin = start - size;
<a name="607" href="#607">607</a>                 <strong>if</strong> (blockBegin &lt; 0)
<a name="608" href="#608">608</a>                 {
<a name="609" href="#609">609</a>                     blockBegin = 0;
<a name="610" href="#610">610</a>                 }
<a name="611" href="#611">611</a>             }
<a name="612" href="#612">612</a>             <strong>else</strong>
<a name="613" href="#613">613</a>             {
<a name="614" href="#614">614</a>                 blockBegin = start;
<a name="615" href="#615">615</a>             }
<a name="616" href="#616">616</a>             blockEnd = blockBegin + memoryLimit - 1;
<a name="617" href="#617">617</a>             startQuery(size);
<a name="618" href="#618">618</a>             <em class="comment">// Re-invoke getResults() to provide the wait processing.</em>
<a name="619" href="#619">619</a>             <strong>return</strong> getResults(start, size);
<a name="620" href="#620">620</a>         }
<a name="621" href="#621">621</a> 
<a name="622" href="#622">622</a>         <em class="comment">// Assume we are moving on, do not retrieve any records prior to start.</em>
<a name="623" href="#623">623</a>         <strong>else</strong> <strong>if</strong> ((start + size - 1) > blockEnd)
<a name="624" href="#624">624</a>         {
<a name="625" href="#625">625</a>             <strong>if</strong> (log.isDebugEnabled())
<a name="626" href="#626">626</a>             {
<a name="627" href="#627">627</a>                 log.debug(<span class="string">"getResults(): Paging past end of loaded data as "</span>
<a name="628" href="#628">628</a>                         + <span class="string">"start+size-1 ("</span> + (start + size - 1)
<a name="629" href="#629">629</a>                         + <span class="string">") > blockEnd ("</span> + blockEnd + <span class="string">")"</span>);
<a name="630" href="#630">630</a>             }
<a name="631" href="#631">631</a>             stopQuery();
<a name="632" href="#632">632</a>             blockBegin = start;
<a name="633" href="#633">633</a>             blockEnd = blockBegin + memoryLimit - 1;
<a name="634" href="#634">634</a>             startQuery(size);
<a name="635" href="#635">635</a>             <em class="comment">// Re-invoke getResults() to provide the wait processing.</em>
<a name="636" href="#636">636</a>             <strong>return</strong> getResults(start, size);
<a name="637" href="#637">637</a>         }
<a name="638" href="#638">638</a> 
<a name="639" href="#639">639</a>         <strong>else</strong>
<a name="640" href="#640">640</a>         {
<a name="641" href="#641">641</a>             <strong>throw</strong> <strong>new</strong> IllegalArgumentException(<span class="string">"Parameter configuration not "</span>
<a name="642" href="#642">642</a>                     + <span class="string">"accounted for."</span>);
<a name="643" href="#643">643</a>         }
<a name="644" href="#644">644</a> 
<a name="645" href="#645">645</a>         <strong>int</strong> fromIndex = start - blockBegin;
<a name="646" href="#646">646</a>         <strong>int</strong> toIndex = fromIndex + Math.min(size, results.size() - fromIndex);
<a name="647" href="#647">647</a> 
<a name="648" href="#648">648</a>         <strong>if</strong> (log.isDebugEnabled())
<a name="649" href="#649">649</a>         {
<a name="650" href="#650">650</a>             log.debug(<span class="string">"getResults(): Retrieving records from results elements "</span>
<a name="651" href="#651">651</a>                     + <span class="string">"start-blockBegin ("</span> + fromIndex + <span class="string">") through "</span>
<a name="652" href="#652">652</a>                     + <span class="string">"fromIndex + Math.min(size, results.size() - fromIndex) ("</span>
<a name="653" href="#653">653</a>                     + toIndex + <span class="string">")"</span>);
<a name="654" href="#654">654</a>         }
<a name="655" href="#655">655</a> 
<a name="656" href="#656">656</a>         List returnResults;
<a name="657" href="#657">657</a> 
<a name="658" href="#658">658</a>         <strong>synchronized</strong> (results)
<a name="659" href="#659">659</a>         {
<a name="660" href="#660">660</a>             returnResults = <strong>new</strong> ArrayList(results.subList(fromIndex, toIndex));
<a name="661" href="#661">661</a>         }
<a name="662" href="#662">662</a> 
<a name="663" href="#663">663</a>         <strong>if</strong> (<strong>null</strong> != returnBuilderClass)
<a name="664" href="#664">664</a>         {
<a name="665" href="#665">665</a>             <em class="comment">// Invoke the populateObjects() method</em>
<a name="666" href="#666">666</a>             Object[] theArgs = { returnResults };
<a name="667" href="#667">667</a>             <strong>try</strong>
<a name="668" href="#668">668</a>             {
<a name="669" href="#669">669</a>                 returnResults = (List) getPopulateObjectsMethod().invoke(
<a name="670" href="#670">670</a>                         returnBuilderClass.newInstance(), theArgs);
<a name="671" href="#671">671</a>             }
<a name="672" href="#672">672</a>             <strong>catch</strong> (Exception e)
<a name="673" href="#673">673</a>             {
<a name="674" href="#674">674</a>                 <strong>throw</strong> <strong>new</strong> <a href="../../../../org/apache/torque/TorqueException.html">TorqueException</a>(<span class="string">"Unable to populate results"</span>, e);
<a name="675" href="#675">675</a>             }
<a name="676" href="#676">676</a>         }
<a name="677" href="#677">677</a>         position = start + size;
<a name="678" href="#678">678</a>         lastResults = returnResults;
<a name="679" href="#679">679</a>         <strong>return</strong> <strong>return</strong>Results;
<a name="680" href="#680">680</a>     }
<a name="681" href="#681">681</a> 
<a name="682" href="#682">682</a>     <em>/**<em>*</em></em>
<a name="683" href="#683">683</a> <em>     * A background thread that retrieves the rows.</em>
<a name="684" href="#684">684</a> <em>     */</em>
<a name="685" href="#685">685</a>     <strong>public</strong> <strong>void</strong> run()
<a name="686" href="#686">686</a>     {
<a name="687" href="#687">687</a>         <strong>boolean</strong> dbSupportsNativeLimit;
<a name="688" href="#688">688</a>         <strong>boolean</strong> dbSupportsNativeOffset;
<a name="689" href="#689">689</a>         <strong>try</strong>
<a name="690" href="#690">690</a>         {
<a name="691" href="#691">691</a>             dbSupportsNativeLimit
<a name="692" href="#692">692</a>                     = (Torque.getDB(dbName).supportsNativeLimit());
<a name="693" href="#693">693</a>             dbSupportsNativeOffset
<a name="694" href="#694">694</a>                     = (Torque.getDB(dbName).supportsNativeOffset());
<a name="695" href="#695">695</a>         }
<a name="696" href="#696">696</a>         <strong>catch</strong> (TorqueException e)
<a name="697" href="#697">697</a>         {
<a name="698" href="#698">698</a>             log.error(<span class="string">"run() : Exiting :"</span>, e);
<a name="699" href="#699">699</a>             <em class="comment">// we cannot execute further because Torque is not initialized</em>
<a name="700" href="#700">700</a>             <em class="comment">// correctly</em>
<a name="701" href="#701">701</a>             <strong>return</strong>;
<a name="702" href="#702">702</a>         }
<a name="703" href="#703">703</a> 
<a name="704" href="#704">704</a>         <strong>int</strong> size;
<a name="705" href="#705">705</a>         <strong>if</strong> (dbSupportsNativeLimit &amp;&amp; dbSupportsNativeOffset)
<a name="706" href="#706">706</a>         {
<a name="707" href="#707">707</a>             <em class="comment">// retrieve one page at a time</em>
<a name="708" href="#708">708</a>             size = pageSize;
<a name="709" href="#709">709</a>         }
<a name="710" href="#710">710</a>         <strong>else</strong>
<a name="711" href="#711">711</a>         {
<a name="712" href="#712">712</a>             <em class="comment">// retrieve the whole block at once and add the offset,</em>
<a name="713" href="#713">713</a>             <em class="comment">// and add one record to check if we have reached the end of the</em>
<a name="714" href="#714">714</a>             <em class="comment">// data</em>
<a name="715" href="#715">715</a>             size = blockBegin + memoryLimit + 1;
<a name="716" href="#716">716</a>         }
<a name="717" href="#717">717</a>         <em class="comment">/*<em class="comment"> The connection to the database. */</em></em>
<a name="718" href="#718">718</a>         Connection conn = <strong>null</strong>;
<a name="719" href="#719">719</a>         <em>/**<em>* Used to retrieve query results from Village. */</em></em>
<a name="720" href="#720">720</a>         QueryDataSet qds = <strong>null</strong>;
<a name="721" href="#721">721</a> 
<a name="722" href="#722">722</a>         <strong>try</strong>
<a name="723" href="#723">723</a>         {
<a name="724" href="#724">724</a>             <em class="comment">// Add 1 to memory limit to check if the query ends on a page break.</em>
<a name="725" href="#725">725</a>             results = <strong>new</strong> ArrayList(memoryLimit + 1);
<a name="726" href="#726">726</a> 
<a name="727" href="#727">727</a>             <em class="comment">// Use the criteria to limit the rows that are retrieved to the</em>
<a name="728" href="#728">728</a>             <em class="comment">// block of records that fit in the predefined memoryLimit.</em>
<a name="729" href="#729">729</a>             <strong>if</strong> (dbSupportsNativeLimit)
<a name="730" href="#730">730</a>             {
<a name="731" href="#731">731</a>                 <strong>if</strong> (dbSupportsNativeOffset)
<a name="732" href="#732">732</a>                 {
<a name="733" href="#733">733</a>                     criteria.setOffset(blockBegin);
<a name="734" href="#734">734</a>                     <em class="comment">// Add 1 to memory limit to check if the query ends on a</em>
<a name="735" href="#735">735</a>                     <em class="comment">// page break.</em>
<a name="736" href="#736">736</a>                     criteria.setLimit(memoryLimit + 1);
<a name="737" href="#737">737</a>                 }
<a name="738" href="#738">738</a>                 <strong>else</strong>
<a name="739" href="#739">739</a>                 {
<a name="740" href="#740">740</a>                     criteria.setLimit(blockBegin + memoryLimit + 1);
<a name="741" href="#741">741</a>                 }
<a name="742" href="#742">742</a>             }
<a name="743" href="#743">743</a> 
<a name="744" href="#744">744</a>             <em class="comment">/*<em class="comment"> </em></em>
<a name="745" href="#745">745</a> <em class="comment">             * Fix criterions relating to booleanint or booleanchar columns</em>
<a name="746" href="#746">746</a> <em class="comment">             * The defaultTableMap parameter in this call is null because we have</em>
<a name="747" href="#747">747</a> <em class="comment">             * no default peer class inside LargeSelect. This means that all</em>
<a name="748" href="#748">748</a> <em class="comment">             * columns not fully qualified will not be modified.</em>
<a name="749" href="#749">749</a> <em class="comment">             */</em>
<a name="750" href="#750">750</a>             BasePeer.correctBooleans(criteria, <strong>null</strong>);
<a name="751" href="#751">751</a>             
<a name="752" href="#752">752</a>             query = BasePeer.createQueryString(criteria);
<a name="753" href="#753">753</a> 
<a name="754" href="#754">754</a>             <em class="comment">// Get a connection to the db.</em>
<a name="755" href="#755">755</a>             conn = Torque.getConnection(dbName);
<a name="756" href="#756">756</a> 
<a name="757" href="#757">757</a>             <em class="comment">// Execute the query.</em>
<a name="758" href="#758">758</a>             <strong>if</strong> (log.isDebugEnabled())
<a name="759" href="#759">759</a>             {
<a name="760" href="#760">760</a>                 log.debug(<span class="string">"run(): query = "</span> + query);
<a name="761" href="#761">761</a>                 log.debug(<span class="string">"run(): memoryLimit = "</span> + memoryLimit);
<a name="762" href="#762">762</a>                 log.debug(<span class="string">"run(): blockBegin = "</span> + blockBegin);
<a name="763" href="#763">763</a>                 log.debug(<span class="string">"run(): blockEnd = "</span> + blockEnd);
<a name="764" href="#764">764</a>             }
<a name="765" href="#765">765</a>             qds = <strong>new</strong> QueryDataSet(conn, query);
<a name="766" href="#766">766</a> 
<a name="767" href="#767">767</a>             <em class="comment">// Continue getting rows one page at a time until the memory limit</em>
<a name="768" href="#768">768</a>             <em class="comment">// is reached, all results have been retrieved, or the rest</em>
<a name="769" href="#769">769</a>             <em class="comment">// of the results have been determined to be irrelevant.</em>
<a name="770" href="#770">770</a>             <strong>while</strong> (!killThread
<a name="771" href="#771">771</a>                 &amp;&amp; !qds.allRecordsRetrieved()
<a name="772" href="#772">772</a>                 &amp;&amp; currentlyFilledTo + pageSize &lt;= blockEnd)
<a name="773" href="#773">773</a>             {
<a name="774" href="#774">774</a>                 <em class="comment">// This caters for when memoryLimit is not a multiple of</em>
<a name="775" href="#775">775</a>                 <em class="comment">//  pageSize which it never is because we always add 1 above.</em>
<a name="776" href="#776">776</a>                 <em class="comment">// not applicable if the db has no native limit where this</em>
<a name="777" href="#777">777</a>                 <em class="comment">// was already considered</em>
<a name="778" href="#778">778</a>                 <strong>if</strong> ((currentlyFilledTo + pageSize) >= blockEnd
<a name="779" href="#779">779</a>                         &amp;&amp; dbSupportsNativeLimit)
<a name="780" href="#780">780</a>                 {
<a name="781" href="#781">781</a>                     <em class="comment">// Add 1 to check if the query ends on a page break.</em>
<a name="782" href="#782">782</a>                     size = blockEnd - currentlyFilledTo + 1;
<a name="783" href="#783">783</a>                 }
<a name="784" href="#784">784</a> 
<a name="785" href="#785">785</a>                 <strong>if</strong> (log.isDebugEnabled())
<a name="786" href="#786">786</a>                 {
<a name="787" href="#787">787</a>                     log.debug(<span class="string">"run(): Invoking BasePeer.getSelectResults(qds, "</span>
<a name="788" href="#788">788</a>                             + size + <span class="string">", false)"</span>);
<a name="789" href="#789">789</a>                 }
<a name="790" href="#790">790</a> 
<a name="791" href="#791">791</a>                 List tempResults
<a name="792" href="#792">792</a>                         = BasePeer.getSelectResults(qds, size, false);
<a name="793" href="#793">793</a> 
<a name="794" href="#794">794</a>                 <strong>int</strong> startIndex = dbSupportsNativeOffset ? 0 : blockBegin;
<a name="795" href="#795">795</a> 
<a name="796" href="#796">796</a>                 <strong>synchronized</strong> (results)
<a name="797" href="#797">797</a>                 {
<a name="798" href="#798">798</a>                     <strong>for</strong> (<strong>int</strong> i = startIndex, n = tempResults.size(); i &lt; n; i++)
<a name="799" href="#799">799</a>                     {
<a name="800" href="#800">800</a>                         results.add(tempResults.get(i));
<a name="801" href="#801">801</a>                     }
<a name="802" href="#802">802</a>                 }
<a name="803" href="#803">803</a> 
<a name="804" href="#804">804</a>                 <strong>if</strong> (dbSupportsNativeLimit &amp;&amp; dbSupportsNativeOffset)
<a name="805" href="#805">805</a>                 {
<a name="806" href="#806">806</a>                     currentlyFilledTo += tempResults.size();
<a name="807" href="#807">807</a>                 }
<a name="808" href="#808">808</a>                 <strong>else</strong>
<a name="809" href="#809">809</a>                 {
<a name="810" href="#810">810</a>                     currentlyFilledTo = tempResults.size() - 1 - blockBegin;
<a name="811" href="#811">811</a>                 }
<a name="812" href="#812">812</a> 
<a name="813" href="#813">813</a>                 <strong>boolean</strong> perhapsLastPage = <strong>true</strong>;
<a name="814" href="#814">814</a> 
<a name="815" href="#815">815</a>                 <em class="comment">// If the extra record was indeed found then we know we are not</em>
<a name="816" href="#816">816</a>                 <em class="comment">// on the last page but we must now get rid of it.</em>
<a name="817" href="#817">817</a>                 <strong>if</strong> ((dbSupportsNativeLimit
<a name="818" href="#818">818</a>                         &amp;&amp; (results.size() == memoryLimit + 1))
<a name="819" href="#819">819</a>                     || (!dbSupportsNativeLimit
<a name="820" href="#820">820</a>                             &amp;&amp; currentlyFilledTo >= memoryLimit))
<a name="821" href="#821">821</a>                 {
<a name="822" href="#822">822</a>                     <strong>synchronized</strong> (results)
<a name="823" href="#823">823</a>                     {
<a name="824" href="#824">824</a>                         results.remove(currentlyFilledTo--);
<a name="825" href="#825">825</a>                     }
<a name="826" href="#826">826</a>                     perhapsLastPage = false;
<a name="827" href="#827">827</a>                 }
<a name="828" href="#828">828</a> 
<a name="829" href="#829">829</a>                 <strong>if</strong> (results.size() > 0
<a name="830" href="#830">830</a>                     &amp;&amp; blockBegin + currentlyFilledTo >= totalRecords)
<a name="831" href="#831">831</a>                 {
<a name="832" href="#832">832</a>                     <em class="comment">// Add 1 because index starts at 0</em>
<a name="833" href="#833">833</a>                     totalRecords = blockBegin + currentlyFilledTo + 1;
<a name="834" href="#834">834</a>                 }
<a name="835" href="#835">835</a> 
<a name="836" href="#836">836</a>                 <em class="comment">// if the db has limited the datasets, we must retrieve all</em>
<a name="837" href="#837">837</a>                 <em class="comment">// datasets. If not, we are always finished because we fetch</em>
<a name="838" href="#838">838</a>                 <em class="comment">// the whole block at once.</em>
<a name="839" href="#839">839</a>                 <strong>if</strong> (qds.allRecordsRetrieved()
<a name="840" href="#840">840</a>                         || !dbSupportsNativeLimit)
<a name="841" href="#841">841</a>                 {
<a name="842" href="#842">842</a>                     queryCompleted = <strong>true</strong>;
<a name="843" href="#843">843</a>                     <em class="comment">// The following ugly condition ensures that the totals are</em>
<a name="844" href="#844">844</a>                     <em class="comment">// not finalized when a user does something like requesting</em>
<a name="845" href="#845">845</a>                     <em class="comment">// a page greater than what exists in the database.</em>
<a name="846" href="#846">846</a>                     <strong>if</strong> (perhapsLastPage
<a name="847" href="#847">847</a>                         &amp;&amp; getCurrentPageNumber() &lt;= getTotalPages())
<a name="848" href="#848">848</a>                     {
<a name="849" href="#849">849</a>                         totalsFinalized = <strong>true</strong>;
<a name="850" href="#850">850</a>                     }
<a name="851" href="#851">851</a>                 }
<a name="852" href="#852">852</a>                 qds.clearRecords();
<a name="853" href="#853">853</a>             }
<a name="854" href="#854">854</a> 
<a name="855" href="#855">855</a>             <strong>if</strong> (log.isDebugEnabled())
<a name="856" href="#856">856</a>             {
<a name="857" href="#857">857</a>                 log.debug(<span class="string">"run(): While loop terminated because either:"</span>);
<a name="858" href="#858">858</a>                 log.debug(<span class="string">"run(): 1. qds.allRecordsRetrieved(): "</span>
<a name="859" href="#859">859</a>                         + qds.allRecordsRetrieved());
<a name="860" href="#860">860</a>                 log.debug(<span class="string">"run(): 2. killThread: "</span> + killThread);
<a name="861" href="#861">861</a>                 log.debug(<span class="string">"run(): 3. !(currentlyFilledTo + size &lt;= blockEnd): !"</span>
<a name="862" href="#862">862</a>                         + (currentlyFilledTo + pageSize &lt;= blockEnd));
<a name="863" href="#863">863</a>                 log.debug(<span class="string">"run(): - currentlyFilledTo: "</span> + currentlyFilledTo);
<a name="864" href="#864">864</a>                 log.debug(<span class="string">"run(): - size: "</span> + pageSize);
<a name="865" href="#865">865</a>                 log.debug(<span class="string">"run(): - blockEnd: "</span> + blockEnd);
<a name="866" href="#866">866</a>                 log.debug(<span class="string">"run(): - results.size(): "</span> + results.size());
<a name="867" href="#867">867</a>             }
<a name="868" href="#868">868</a>         }
<a name="869" href="#869">869</a>         <strong>catch</strong> (TorqueException e)
<a name="870" href="#870">870</a>         {
<a name="871" href="#871">871</a>             log.error(e);
<a name="872" href="#872">872</a>         }
<a name="873" href="#873">873</a>         <strong>catch</strong> (SQLException e)
<a name="874" href="#874">874</a>         {
<a name="875" href="#875">875</a>             log.error(e);
<a name="876" href="#876">876</a>         }
<a name="877" href="#877">877</a>         <strong>catch</strong> (DataSetException e)
<a name="878" href="#878">878</a>         {
<a name="879" href="#879">879</a>             log.error(e);
<a name="880" href="#880">880</a>         }
<a name="881" href="#881">881</a>         <strong>finally</strong>
<a name="882" href="#882">882</a>         {
<a name="883" href="#883">883</a>             <strong>try</strong>
<a name="884" href="#884">884</a>             {
<a name="885" href="#885">885</a>                 <strong>if</strong> (qds != <strong>null</strong>)
<a name="886" href="#886">886</a>                 {
<a name="887" href="#887">887</a>                     qds.close();
<a name="888" href="#888">888</a>                 }
<a name="889" href="#889">889</a>                 Torque.closeConnection(conn);
<a name="890" href="#890">890</a>             }
<a name="891" href="#891">891</a>             <strong>catch</strong> (SQLException e)
<a name="892" href="#892">892</a>             {
<a name="893" href="#893">893</a>                 log.error(e);
<a name="894" href="#894">894</a>             }
<a name="895" href="#895">895</a>             <strong>catch</strong> (DataSetException e)
<a name="896" href="#896">896</a>             {
<a name="897" href="#897">897</a>                 log.error(e);
<a name="898" href="#898">898</a>             }
<a name="899" href="#899">899</a>             threadRunning = false;
<a name="900" href="#900">900</a>         }
<a name="901" href="#901">901</a>     }
<a name="902" href="#902">902</a> 
<a name="903" href="#903">903</a>     <em>/**<em>*</em></em>
<a name="904" href="#904">904</a> <em>     * Starts a new thread to retrieve the result set.</em>
<a name="905" href="#905">905</a> <em>     *</em>
<a name="906" href="#906">906</a> <em>     * @param initialSize the initial size for each block.</em>
<a name="907" href="#907">907</a> <em>     */</em>
<a name="908" href="#908">908</a>     <strong>private</strong> <strong>synchronized</strong> <strong>void</strong> startQuery(<strong>int</strong> initialSize)
<a name="909" href="#909">909</a>     {
<a name="910" href="#910">910</a>         <strong>if</strong> (!threadRunning)
<a name="911" href="#911">911</a>         {
<a name="912" href="#912">912</a>             pageSize = initialSize;
<a name="913" href="#913">913</a>             currentlyFilledTo = -1;
<a name="914" href="#914">914</a>             queryCompleted = false;
<a name="915" href="#915">915</a>             thread = <strong>new</strong> Thread(<strong>this</strong>);
<a name="916" href="#916">916</a>             thread.start();
<a name="917" href="#917">917</a>             threadRunning = <strong>true</strong>;
<a name="918" href="#918">918</a>         }
<a name="919" href="#919">919</a>     }
<a name="920" href="#920">920</a> 
<a name="921" href="#921">921</a>     <em>/**<em>*</em></em>
<a name="922" href="#922">922</a> <em>     * Used to stop filling the memory with the current block of results, if it</em>
<a name="923" href="#923">923</a> <em>     * has been determined that they are no longer relevant.</em>
<a name="924" href="#924">924</a> <em>     *</em>
<a name="925" href="#925">925</a> <em>     * @throws TorqueException if a sleep is interrupted.</em>
<a name="926" href="#926">926</a> <em>     */</em>
<a name="927" href="#927">927</a>     <strong>private</strong> <strong>synchronized</strong> <strong>void</strong> stopQuery() throws TorqueException
<a name="928" href="#928">928</a>     {
<a name="929" href="#929">929</a>         <strong>if</strong> (threadRunning)
<a name="930" href="#930">930</a>         {
<a name="931" href="#931">931</a>             killThread = <strong>true</strong>;
<a name="932" href="#932">932</a>             <strong>while</strong> (thread.isAlive())
<a name="933" href="#933">933</a>             {
<a name="934" href="#934">934</a>                 <strong>try</strong>
<a name="935" href="#935">935</a>                 {
<a name="936" href="#936">936</a>                     Thread.sleep(QUERY_STOP_SLEEP_TIME);
<a name="937" href="#937">937</a>                 }
<a name="938" href="#938">938</a>                 <strong>catch</strong> (InterruptedException e)
<a name="939" href="#939">939</a>                 {
<a name="940" href="#940">940</a>                     <strong>throw</strong> <strong>new</strong> <a href="../../../../org/apache/torque/TorqueException.html">TorqueException</a>(<span class="string">"Unexpected interruption"</span>, e);
<a name="941" href="#941">941</a>                 }
<a name="942" href="#942">942</a>             }
<a name="943" href="#943">943</a>             killThread = false;
<a name="944" href="#944">944</a>         }
<a name="945" href="#945">945</a>     }
<a name="946" href="#946">946</a> 
<a name="947" href="#947">947</a>     <em>/**<em>*</em></em>
<a name="948" href="#948">948</a> <em>     * Retrieve the number of the current page.</em>
<a name="949" href="#949">949</a> <em>     *</em>
<a name="950" href="#950">950</a> <em>     * @return the current page number.</em>
<a name="951" href="#951">951</a> <em>     */</em>
<a name="952" href="#952">952</a>     <strong>public</strong> <strong>int</strong> getCurrentPageNumber()
<a name="953" href="#953">953</a>     {
<a name="954" href="#954">954</a>         <strong>return</strong> position / pageSize;
<a name="955" href="#955">955</a>     }
<a name="956" href="#956">956</a> 
<a name="957" href="#957">957</a>     <em>/**<em>*</em></em>
<a name="958" href="#958">958</a> <em>     * Retrieve the total number of search result records that are known to</em>
<a name="959" href="#959">959</a> <em>     * exist (this will be the actual value when the query has completeted (see</em>
<a name="960" href="#960">960</a> <em>     * &lt;code>getTotalsFinalized()&lt;/code>).  The convenience method</em>
<a name="961" href="#961">961</a> <em>     * &lt;code>getRecordProgressText()&lt;/code> may be more useful for presenting to</em>
<a name="962" href="#962">962</a> <em>     * users.</em>
<a name="963" href="#963">963</a> <em>     *</em>
<a name="964" href="#964">964</a> <em>     * @return the number of result records known to exist (not accurate until</em>
<a name="965" href="#965">965</a> <em>     * &lt;code>getTotalsFinalized()&lt;/code> returns &lt;code>true&lt;/code>).</em>
<a name="966" href="#966">966</a> <em>     */</em>
<a name="967" href="#967">967</a>     <strong>public</strong> <strong>int</strong> getTotalRecords()
<a name="968" href="#968">968</a>     {
<a name="969" href="#969">969</a>         <strong>return</strong> totalRecords;
<a name="970" href="#970">970</a>     }
<a name="971" href="#971">971</a> 
<a name="972" href="#972">972</a>     <em>/**<em>*</em></em>
<a name="973" href="#973">973</a> <em>     * Provide an indication of whether or not paging of results will be</em>
<a name="974" href="#974">974</a> <em>     * required.</em>
<a name="975" href="#975">975</a> <em>     *</em>
<a name="976" href="#976">976</a> <em>     * @return &lt;code>true&lt;/code> when multiple pages of results exist.</em>
<a name="977" href="#977">977</a> <em>     */</em>
<a name="978" href="#978">978</a>     <strong>public</strong> <strong>boolean</strong> getPaginated()
<a name="979" href="#979">979</a>     {
<a name="980" href="#980">980</a>         <em class="comment">// Handle a page memory limit of 1 page.</em>
<a name="981" href="#981">981</a>         <strong>if</strong> (!getTotalsFinalized())
<a name="982" href="#982">982</a>         {
<a name="983" href="#983">983</a>             <strong>return</strong> <strong>true</strong>;
<a name="984" href="#984">984</a>         }
<a name="985" href="#985">985</a>         <strong>return</strong> blockBegin + currentlyFilledTo + 1 > pageSize;
<a name="986" href="#986">986</a>     }
<a name="987" href="#987">987</a> 
<a name="988" href="#988">988</a>     <em>/**<em>*</em></em>
<a name="989" href="#989">989</a> <em>     * Retrieve the total number of pages of search results that are known to</em>
<a name="990" href="#990">990</a> <em>     * exist (this will be the actual value when the query has completeted (see</em>
<a name="991" href="#991">991</a> <em>     * &lt;code>getQyeryCompleted()&lt;/code>).  The convenience method</em>
<a name="992" href="#992">992</a> <em>     * &lt;code>getPageProgressText()&lt;/code> may be more useful for presenting to</em>
<a name="993" href="#993">993</a> <em>     * users.</em>
<a name="994" href="#994">994</a> <em>     *</em>
<a name="995" href="#995">995</a> <em>     * @return the number of pages of results known to exist (not accurate until</em>
<a name="996" href="#996">996</a> <em>     * &lt;code>getTotalsFinalized()&lt;/code> returns &lt;code>true&lt;/code>).</em>
<a name="997" href="#997">997</a> <em>     */</em>
<a name="998" href="#998">998</a>     <strong>public</strong> <strong>int</strong> getTotalPages()
<a name="999" href="#999">999</a>     {
<a name="1000" href="#1000">1000</a>         <strong>if</strong> (totalPages > -1)
<a name="1001" href="#1001">1001</a>         {
<a name="1002" href="#1002">1002</a>             <strong>return</strong> totalPages;
<a name="1003" href="#1003">1003</a>         }
<a name="1004" href="#1004">1004</a> 
<a name="1005" href="#1005">1005</a>         <strong>int</strong> tempPageCount =  getTotalRecords() / pageSize
<a name="1006" href="#1006">1006</a>                 + (getTotalRecords() % pageSize > 0 ? 1 : 0);
<a name="1007" href="#1007">1007</a> 
<a name="1008" href="#1008">1008</a>         <strong>if</strong> (getTotalsFinalized())
<a name="1009" href="#1009">1009</a>         {
<a name="1010" href="#1010">1010</a>             totalPages = tempPageCount;
<a name="1011" href="#1011">1011</a>         }
<a name="1012" href="#1012">1012</a> 
<a name="1013" href="#1013">1013</a>         <strong>return</strong> tempPageCount;
<a name="1014" href="#1014">1014</a>     }
<a name="1015" href="#1015">1015</a> 
<a name="1016" href="#1016">1016</a>     <em>/**<em>*</em></em>
<a name="1017" href="#1017">1017</a> <em>     * Retrieve the page size.</em>
<a name="1018" href="#1018">1018</a> <em>     *</em>
<a name="1019" href="#1019">1019</a> <em>     * @return the number of records returned on each invocation of</em>
<a name="1020" href="#1020">1020</a> <em>     * &lt;code>getNextResults()&lt;/code>/&lt;code>getPreviousResults()&lt;/code>.</em>
<a name="1021" href="#1021">1021</a> <em>     */</em>
<a name="1022" href="#1022">1022</a>     <strong>public</strong> <strong>int</strong> getPageSize()
<a name="1023" href="#1023">1023</a>     {
<a name="1024" href="#1024">1024</a>         <strong>return</strong> pageSize;
<a name="1025" href="#1025">1025</a>     }
<a name="1026" href="#1026">1026</a> 
<a name="1027" href="#1027">1027</a>     <em>/**<em>*</em></em>
<a name="1028" href="#1028">1028</a> <em>     * Provide access to indicator that the total values for the number of</em>
<a name="1029" href="#1029">1029</a> <em>     * records and pages are now accurate as opposed to known upper limits.</em>
<a name="1030" href="#1030">1030</a> <em>     *</em>
<a name="1031" href="#1031">1031</a> <em>     * @return &lt;code>true&lt;/code> when the totals are known to have been fully</em>
<a name="1032" href="#1032">1032</a> <em>     * computed.</em>
<a name="1033" href="#1033">1033</a> <em>     */</em>
<a name="1034" href="#1034">1034</a>     <strong>public</strong> <strong>boolean</strong> getTotalsFinalized()
<a name="1035" href="#1035">1035</a>     {
<a name="1036" href="#1036">1036</a>         <strong>return</strong> totalsFinalized;
<a name="1037" href="#1037">1037</a>     }
<a name="1038" href="#1038">1038</a> 
<a name="1039" href="#1039">1039</a>     <em>/**<em>*</em></em>
<a name="1040" href="#1040">1040</a> <em>     * Provide a way of changing the more pages/records indicator.</em>
<a name="1041" href="#1041">1041</a> <em>     *</em>
<a name="1042" href="#1042">1042</a> <em>     * @param moreIndicator the indicator to use in place of the default</em>
<a name="1043" href="#1043">1043</a> <em>     * ("&amp;gt;").</em>
<a name="1044" href="#1044">1044</a> <em>     */</em>
<a name="1045" href="#1045">1045</a>     <strong>public</strong> <strong>static</strong> <strong>void</strong> setMoreIndicator(String moreIndicator)
<a name="1046" href="#1046">1046</a>     {
<a name="1047" href="#1047">1047</a>         LargeSelect.moreIndicator = moreIndicator;
<a name="1048" href="#1048">1048</a>     }
<a name="1049" href="#1049">1049</a> 
<a name="1050" href="#1050">1050</a>     <em>/**<em>*</em></em>
<a name="1051" href="#1051">1051</a> <em>     * Retrieve the more pages/records indicator.</em>
<a name="1052" href="#1052">1052</a> <em>     */</em>
<a name="1053" href="#1053">1053</a>     <strong>public</strong> <strong>static</strong> String getMoreIndicator()
<a name="1054" href="#1054">1054</a>     {
<a name="1055" href="#1055">1055</a>         <strong>return</strong> LargeSelect.moreIndicator;
<a name="1056" href="#1056">1056</a>     }
<a name="1057" href="#1057">1057</a> 
<a name="1058" href="#1058">1058</a>     <em>/**<em>*</em></em>
<a name="1059" href="#1059">1059</a> <em>     * Sets the multiplier that will be used to compute the memory limit when a</em>
<a name="1060" href="#1060">1060</a> <em>     * constructor with no memory page limit is used - the memory limit will be</em>
<a name="1061" href="#1061">1061</a> <em>     * this number multiplied by the page size.</em>
<a name="1062" href="#1062">1062</a> <em>     *</em>
<a name="1063" href="#1063">1063</a> <em>     * @param memoryPageLimit the maximum number of pages to be in memory</em>
<a name="1064" href="#1064">1064</a> <em>     * at one time.</em>
<a name="1065" href="#1065">1065</a> <em>     */</em>
<a name="1066" href="#1066">1066</a>     <strong>public</strong> <strong>static</strong> <strong>void</strong> setMemoryPageLimit(<strong>int</strong> memoryPageLimit)
<a name="1067" href="#1067">1067</a>     {
<a name="1068" href="#1068">1068</a>         LargeSelect.memoryPageLimit = memoryPageLimit;
<a name="1069" href="#1069">1069</a>     }
<a name="1070" href="#1070">1070</a> 
<a name="1071" href="#1071">1071</a>     <em>/**<em>*</em></em>
<a name="1072" href="#1072">1072</a> <em>     * Retrieves the multiplier that will be used to compute the memory limit</em>
<a name="1073" href="#1073">1073</a> <em>     * when a constructor with no memory page limit is used - the memory limit</em>
<a name="1074" href="#1074">1074</a> <em>     * will be this number multiplied by the page size.</em>
<a name="1075" href="#1075">1075</a> <em>     */</em>
<a name="1076" href="#1076">1076</a>     <strong>public</strong> <strong>static</strong> <strong>int</strong> getMemoryPageLimit()
<a name="1077" href="#1077">1077</a>     {
<a name="1078" href="#1078">1078</a>         <strong>return</strong> LargeSelect.memoryPageLimit;
<a name="1079" href="#1079">1079</a>     }
<a name="1080" href="#1080">1080</a> 
<a name="1081" href="#1081">1081</a>     <em>/**<em>*</em></em>
<a name="1082" href="#1082">1082</a> <em>     * A convenience method that provides text showing progress through the</em>
<a name="1083" href="#1083">1083</a> <em>     * selected rows on a page basis.</em>
<a name="1084" href="#1084">1084</a> <em>     *</em>
<a name="1085" href="#1085">1085</a> <em>     * @return progress text in the form of "1 of &amp;gt; 5" where "&amp;gt;" can be</em>
<a name="1086" href="#1086">1086</a> <em>     * configured using &lt;code>setMoreIndicator()&lt;/code>.</em>
<a name="1087" href="#1087">1087</a> <em>     */</em>
<a name="1088" href="#1088">1088</a>     <strong>public</strong> String getPageProgressText()
<a name="1089" href="#1089">1089</a>     {
<a name="1090" href="#1090">1090</a>         StringBuffer result = <strong>new</strong> StringBuffer();
<a name="1091" href="#1091">1091</a>         result.append(getCurrentPageNumber());
<a name="1092" href="#1092">1092</a>         result.append(<span class="string">" of "</span>);
<a name="1093" href="#1093">1093</a>         <strong>if</strong> (!totalsFinalized)
<a name="1094" href="#1094">1094</a>         {
<a name="1095" href="#1095">1095</a>             result.append(moreIndicator);
<a name="1096" href="#1096">1096</a>             result.append(<span class="string">" "</span>);
<a name="1097" href="#1097">1097</a>         }
<a name="1098" href="#1098">1098</a>         result.append(getTotalPages());
<a name="1099" href="#1099">1099</a>         <strong>return</strong> result.toString();
<a name="1100" href="#1100">1100</a>     }
<a name="1101" href="#1101">1101</a> 
<a name="1102" href="#1102">1102</a>     <em>/**<em>*</em></em>
<a name="1103" href="#1103">1103</a> <em>     * Provides a count of the number of rows to be displayed on the current</em>
<a name="1104" href="#1104">1104</a> <em>     * page - for the last page this may be less than the configured page size.</em>
<a name="1105" href="#1105">1105</a> <em>     *</em>
<a name="1106" href="#1106">1106</a> <em>     * @return the number of records that are included on the current page of</em>
<a name="1107" href="#1107">1107</a> <em>     * results.</em>
<a name="1108" href="#1108">1108</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="1109" href="#1109">1109</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="1110" href="#1110">1110</a> <em>     */</em>
<a name="1111" href="#1111">1111</a>     <strong>public</strong> <strong>int</strong> getCurrentPageSize() throws TorqueException
<a name="1112" href="#1112">1112</a>     {
<a name="1113" href="#1113">1113</a>         <strong>if</strong> (<strong>null</strong> == getCurrentPageResults())
<a name="1114" href="#1114">1114</a>         {
<a name="1115" href="#1115">1115</a>             <strong>return</strong> 0;
<a name="1116" href="#1116">1116</a>         }
<a name="1117" href="#1117">1117</a>         <strong>return</strong> getCurrentPageResults().size();
<a name="1118" href="#1118">1118</a>     }
<a name="1119" href="#1119">1119</a> 
<a name="1120" href="#1120">1120</a>     <em>/**<em>*</em></em>
<a name="1121" href="#1121">1121</a> <em>     * Provide the record number of the first row included on the current page.</em>
<a name="1122" href="#1122">1122</a> <em>     *</em>
<a name="1123" href="#1123">1123</a> <em>     * @return The record number of the first row of the current page.</em>
<a name="1124" href="#1124">1124</a> <em>     */</em>
<a name="1125" href="#1125">1125</a>     <strong>public</strong> <strong>int</strong> getFirstRecordNoForPage()
<a name="1126" href="#1126">1126</a>     {
<a name="1127" href="#1127">1127</a>         <strong>if</strong> (getCurrentPageNumber() &lt; 1)
<a name="1128" href="#1128">1128</a>         {
<a name="1129" href="#1129">1129</a>             <strong>return</strong> 0;
<a name="1130" href="#1130">1130</a>         }
<a name="1131" href="#1131">1131</a>         <strong>return</strong> (getCurrentPageNumber() - 1) * getPageSize() + 1;
<a name="1132" href="#1132">1132</a>     }
<a name="1133" href="#1133">1133</a> 
<a name="1134" href="#1134">1134</a>     <em>/**<em>*</em></em>
<a name="1135" href="#1135">1135</a> <em>     * Provide the record number of the last row included on the current page.</em>
<a name="1136" href="#1136">1136</a> <em>     *</em>
<a name="1137" href="#1137">1137</a> <em>     * @return the record number of the last row of the current page.</em>
<a name="1138" href="#1138">1138</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="1139" href="#1139">1139</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="1140" href="#1140">1140</a> <em>     */</em>
<a name="1141" href="#1141">1141</a>     <strong>public</strong> <strong>int</strong> getLastRecordNoForPage() throws TorqueException
<a name="1142" href="#1142">1142</a>     {
<a name="1143" href="#1143">1143</a>         <strong>if</strong> (0 == getCurrentPageNumber())
<a name="1144" href="#1144">1144</a>         {
<a name="1145" href="#1145">1145</a>             <strong>return</strong> 0;
<a name="1146" href="#1146">1146</a>         }
<a name="1147" href="#1147">1147</a>         <strong>return</strong> (getCurrentPageNumber() - 1) * getPageSize()
<a name="1148" href="#1148">1148</a>                 + getCurrentPageSize();
<a name="1149" href="#1149">1149</a>     }
<a name="1150" href="#1150">1150</a> 
<a name="1151" href="#1151">1151</a>     <em>/**<em>*</em></em>
<a name="1152" href="#1152">1152</a> <em>     * A convenience method that provides text showing progress through the</em>
<a name="1153" href="#1153">1153</a> <em>     * selected rows on a record basis.</em>
<a name="1154" href="#1154">1154</a> <em>     *</em>
<a name="1155" href="#1155">1155</a> <em>     * @return progress text in the form of "26 - 50 of &amp;gt; 250" where "&amp;gt;"</em>
<a name="1156" href="#1156">1156</a> <em>     * can be configured using &lt;code>setMoreIndicator()&lt;/code>.</em>
<a name="1157" href="#1157">1157</a> <em>     * @throws TorqueException if invoking the &lt;code>populateObjects()&lt;code></em>
<a name="1158" href="#1158">1158</a> <em>     * method runs into problems or a sleep is unexpectedly interrupted.</em>
<a name="1159" href="#1159">1159</a> <em>     */</em>
<a name="1160" href="#1160">1160</a>     <strong>public</strong> String getRecordProgressText() throws TorqueException
<a name="1161" href="#1161">1161</a>     {
<a name="1162" href="#1162">1162</a>         StringBuffer result = <strong>new</strong> StringBuffer();
<a name="1163" href="#1163">1163</a>         result.append(getFirstRecordNoForPage());
<a name="1164" href="#1164">1164</a>         result.append(<span class="string">" - "</span>);
<a name="1165" href="#1165">1165</a>         result.append(getLastRecordNoForPage());
<a name="1166" href="#1166">1166</a>         result.append(<span class="string">" of "</span>);
<a name="1167" href="#1167">1167</a>         <strong>if</strong> (!totalsFinalized)
<a name="1168" href="#1168">1168</a>         {
<a name="1169" href="#1169">1169</a>             result.append(moreIndicator);
<a name="1170" href="#1170">1170</a>             result.append(<span class="string">" "</span>);
<a name="1171" href="#1171">1171</a>         }
<a name="1172" href="#1172">1172</a>         result.append(getTotalRecords());
<a name="1173" href="#1173">1173</a>         <strong>return</strong> result.toString();
<a name="1174" href="#1174">1174</a>     }
<a name="1175" href="#1175">1175</a> 
<a name="1176" href="#1176">1176</a>     <em>/**<em>*</em></em>
<a name="1177" href="#1177">1177</a> <em>     * Indicates if further result pages are available.</em>
<a name="1178" href="#1178">1178</a> <em>     *</em>
<a name="1179" href="#1179">1179</a> <em>     * @return &lt;code>true&lt;/code> when further results are available.</em>
<a name="1180" href="#1180">1180</a> <em>     */</em>
<a name="1181" href="#1181">1181</a>     <strong>public</strong> <strong>boolean</strong> getNextResultsAvailable()
<a name="1182" href="#1182">1182</a>     {
<a name="1183" href="#1183">1183</a>         <strong>if</strong> (!totalsFinalized || getCurrentPageNumber() &lt; getTotalPages())
<a name="1184" href="#1184">1184</a>         {
<a name="1185" href="#1185">1185</a>             <strong>return</strong> <strong>true</strong>;
<a name="1186" href="#1186">1186</a>         }
<a name="1187" href="#1187">1187</a>         <strong>return</strong> false;
<a name="1188" href="#1188">1188</a>     }
<a name="1189" href="#1189">1189</a> 
<a name="1190" href="#1190">1190</a>     <em>/**<em>*</em></em>
<a name="1191" href="#1191">1191</a> <em>     * Indicates if previous results pages are available.</em>
<a name="1192" href="#1192">1192</a> <em>     *</em>
<a name="1193" href="#1193">1193</a> <em>     * @return &lt;code>true&lt;/code> when previous results are available.</em>
<a name="1194" href="#1194">1194</a> <em>     */</em>
<a name="1195" href="#1195">1195</a>     <strong>public</strong> <strong>boolean</strong> getPreviousResultsAvailable()
<a name="1196" href="#1196">1196</a>     {
<a name="1197" href="#1197">1197</a>         <strong>if</strong> (getCurrentPageNumber() &lt;= 1)
<a name="1198" href="#1198">1198</a>         {
<a name="1199" href="#1199">1199</a>             <strong>return</strong> false;
<a name="1200" href="#1200">1200</a>         }
<a name="1201" href="#1201">1201</a>         <strong>return</strong> <strong>true</strong>;
<a name="1202" href="#1202">1202</a>     }
<a name="1203" href="#1203">1203</a> 
<a name="1204" href="#1204">1204</a>     <em>/**<em>*</em></em>
<a name="1205" href="#1205">1205</a> <em>     * Indicates if any results are available.</em>
<a name="1206" href="#1206">1206</a> <em>     *</em>
<a name="1207" href="#1207">1207</a> <em>     * @return &lt;code>true&lt;/code> of any results are available.</em>
<a name="1208" href="#1208">1208</a> <em>     */</em>
<a name="1209" href="#1209">1209</a>     <strong>public</strong> <strong>boolean</strong> hasResultsAvailable()
<a name="1210" href="#1210">1210</a>     {
<a name="1211" href="#1211">1211</a>         <strong>return</strong> getTotalRecords() > 0;
<a name="1212" href="#1212">1212</a>     }
<a name="1213" href="#1213">1213</a> 
<a name="1214" href="#1214">1214</a>     <em>/**<em>*</em></em>
<a name="1215" href="#1215">1215</a> <em>     * Clear the query result so that the query is reexecuted when the next page</em>
<a name="1216" href="#1216">1216</a> <em>     * is retrieved.  You may want to invoke this method if you are returning to</em>
<a name="1217" href="#1217">1217</a> <em>     * a page after performing an operation on an item in the result set.</em>
<a name="1218" href="#1218">1218</a> <em>     *</em>
<a name="1219" href="#1219">1219</a> <em>     * @throws TorqueException if a sleep is interrupted.</em>
<a name="1220" href="#1220">1220</a> <em>     */</em>
<a name="1221" href="#1221">1221</a>     <strong>public</strong> <strong>synchronized</strong> <strong>void</strong> invalidateResult() throws TorqueException
<a name="1222" href="#1222">1222</a>     {
<a name="1223" href="#1223">1223</a>         stopQuery();
<a name="1224" href="#1224">1224</a>         blockBegin = 0;
<a name="1225" href="#1225">1225</a>         blockEnd = 0;
<a name="1226" href="#1226">1226</a>         currentlyFilledTo = -1;
<a name="1227" href="#1227">1227</a>         results = <strong>null</strong>;
<a name="1228" href="#1228">1228</a>         <em class="comment">// TODO Perhaps store the oldPosition and immediately restart the</em>
<a name="1229" href="#1229">1229</a>         <em class="comment">// query.</em>
<a name="1230" href="#1230">1230</a>         <em class="comment">// oldPosition = position;</em>
<a name="1231" href="#1231">1231</a>         position = 0;
<a name="1232" href="#1232">1232</a>         totalPages = -1;
<a name="1233" href="#1233">1233</a>         totalRecords = 0;
<a name="1234" href="#1234">1234</a>         queryCompleted = false;
<a name="1235" href="#1235">1235</a>         totalsFinalized = false;
<a name="1236" href="#1236">1236</a>         lastResults = <strong>null</strong>;
<a name="1237" href="#1237">1237</a>     }
<a name="1238" href="#1238">1238</a> 
<a name="1239" href="#1239">1239</a>     <em>/**<em>*</em></em>
<a name="1240" href="#1240">1240</a> <em>     * Retrieve a search parameter.  This acts as a convenient place to store</em>
<a name="1241" href="#1241">1241</a> <em>     * parameters that relate to the LargeSelect to make it easy to get at them</em>
<a name="1242" href="#1242">1242</a> <em>     * in order to repopulate search parameters on a form when the next page of</em>
<a name="1243" href="#1243">1243</a> <em>     * results is retrieved - they in no way effect the operation of</em>
<a name="1244" href="#1244">1244</a> <em>     * LargeSelect.</em>
<a name="1245" href="#1245">1245</a> <em>     *</em>
<a name="1246" href="#1246">1246</a> <em>     * @param name the search parameter key to retrieve.</em>
<a name="1247" href="#1247">1247</a> <em>     * @return the value of the search parameter.</em>
<a name="1248" href="#1248">1248</a> <em>     */</em>
<a name="1249" href="#1249">1249</a>     <strong>public</strong> String getSearchParam(String name)
<a name="1250" href="#1250">1250</a>     {
<a name="1251" href="#1251">1251</a>         <strong>return</strong> getSearchParam(name, <strong>null</strong>);
<a name="1252" href="#1252">1252</a>     }
<a name="1253" href="#1253">1253</a> 
<a name="1254" href="#1254">1254</a>     <em>/**<em>*</em></em>
<a name="1255" href="#1255">1255</a> <em>     * Retrieve a search parameter.  This acts as a convenient place to store</em>
<a name="1256" href="#1256">1256</a> <em>     * parameters that relate to the LargeSelect to make it easy to get at them</em>
<a name="1257" href="#1257">1257</a> <em>     * in order to repopulate search parameters on a form when the next page of</em>
<a name="1258" href="#1258">1258</a> <em>     * results is retrieved - they in no way effect the operation of</em>
<a name="1259" href="#1259">1259</a> <em>     * LargeSelect.</em>
<a name="1260" href="#1260">1260</a> <em>     *</em>
<a name="1261" href="#1261">1261</a> <em>     * @param name the search parameter key to retrieve.</em>
<a name="1262" href="#1262">1262</a> <em>     * @param defaultValue the default value to return if the key is not found.</em>
<a name="1263" href="#1263">1263</a> <em>     * @return the value of the search parameter.</em>
<a name="1264" href="#1264">1264</a> <em>     */</em>
<a name="1265" href="#1265">1265</a>     <strong>public</strong> String getSearchParam(String name, String defaultValue)
<a name="1266" href="#1266">1266</a>     {
<a name="1267" href="#1267">1267</a>         <strong>if</strong> (<strong>null</strong> == params)
<a name="1268" href="#1268">1268</a>         {
<a name="1269" href="#1269">1269</a>             <strong>return</strong> defaultValue;
<a name="1270" href="#1270">1270</a>         }
<a name="1271" href="#1271">1271</a>         String value = (String) params.get(name);
<a name="1272" href="#1272">1272</a>         <strong>return</strong> <strong>null</strong> == value ? defaultValue : value;
<a name="1273" href="#1273">1273</a>     }
<a name="1274" href="#1274">1274</a> 
<a name="1275" href="#1275">1275</a>     <em>/**<em>*</em></em>
<a name="1276" href="#1276">1276</a> <em>     * Set a search parameter.  If the value is &lt;code>null&lt;/code> then the</em>
<a name="1277" href="#1277">1277</a> <em>     * key will be removed from the parameters.</em>
<a name="1278" href="#1278">1278</a> <em>     *</em>
<a name="1279" href="#1279">1279</a> <em>     * @param name the search parameter key to set.</em>
<a name="1280" href="#1280">1280</a> <em>     * @param value the value of the search parameter to store.</em>
<a name="1281" href="#1281">1281</a> <em>     */</em>
<a name="1282" href="#1282">1282</a>     <strong>public</strong> <strong>void</strong> setSearchParam(String name, String value)
<a name="1283" href="#1283">1283</a>     {
<a name="1284" href="#1284">1284</a>         <strong>if</strong> (<strong>null</strong> == value)
<a name="1285" href="#1285">1285</a>         {
<a name="1286" href="#1286">1286</a>             removeSearchParam(name);
<a name="1287" href="#1287">1287</a>         }
<a name="1288" href="#1288">1288</a>         <strong>else</strong>
<a name="1289" href="#1289">1289</a>         {
<a name="1290" href="#1290">1290</a>             <strong>if</strong> (<strong>null</strong> != name)
<a name="1291" href="#1291">1291</a>             {
<a name="1292" href="#1292">1292</a>                 <strong>if</strong> (<strong>null</strong> == params)
<a name="1293" href="#1293">1293</a>                 {
<a name="1294" href="#1294">1294</a>                     params = <strong>new</strong> Hashtable();
<a name="1295" href="#1295">1295</a>                 }
<a name="1296" href="#1296">1296</a>                 params.put(name, value);
<a name="1297" href="#1297">1297</a>             }
<a name="1298" href="#1298">1298</a>         }
<a name="1299" href="#1299">1299</a>     }
<a name="1300" href="#1300">1300</a> 
<a name="1301" href="#1301">1301</a>     <em>/**<em>*</em></em>
<a name="1302" href="#1302">1302</a> <em>     * Remove a value from the search parameters.</em>
<a name="1303" href="#1303">1303</a> <em>     *</em>
<a name="1304" href="#1304">1304</a> <em>     * @param name the search parameter key to remove.</em>
<a name="1305" href="#1305">1305</a> <em>     */</em>
<a name="1306" href="#1306">1306</a>     <strong>public</strong> <strong>void</strong> removeSearchParam(String name)
<a name="1307" href="#1307">1307</a>     {
<a name="1308" href="#1308">1308</a>         <strong>if</strong> (<strong>null</strong> != params)
<a name="1309" href="#1309">1309</a>         {
<a name="1310" href="#1310">1310</a>             params.remove(name);
<a name="1311" href="#1311">1311</a>         }
<a name="1312" href="#1312">1312</a>     }
<a name="1313" href="#1313">1313</a> 
<a name="1314" href="#1314">1314</a>     <em>/**<em>*</em></em>
<a name="1315" href="#1315">1315</a> <em>     * Deserialize this LargeSelect instance.</em>
<a name="1316" href="#1316">1316</a> <em>     *</em>
<a name="1317" href="#1317">1317</a> <em>     * @param inputStream The serialization input stream.</em>
<a name="1318" href="#1318">1318</a> <em>     * @throws IOException</em>
<a name="1319" href="#1319">1319</a> <em>     * @throws ClassNotFoundException</em>
<a name="1320" href="#1320">1320</a> <em>     */</em>
<a name="1321" href="#1321">1321</a>     <strong>private</strong> <strong>void</strong> readObject(ObjectInputStream inputStream)
<a name="1322" href="#1322">1322</a>             throws IOException, ClassNotFoundException
<a name="1323" href="#1323">1323</a>     {
<a name="1324" href="#1324">1324</a>         inputStream.defaultReadObject();
<a name="1325" href="#1325">1325</a> 
<a name="1326" href="#1326">1326</a>         <em class="comment">// avoid NPE because of Tomcat de-serialization of sessions</em>
<a name="1327" href="#1327">1327</a>         <strong>if</strong> (Torque.isInit())
<a name="1328" href="#1328">1328</a>         {
<a name="1329" href="#1329">1329</a>             startQuery(pageSize);
<a name="1330" href="#1330">1330</a>         }
<a name="1331" href="#1331">1331</a>     }
<a name="1332" href="#1332">1332</a> 
<a name="1333" href="#1333">1333</a>     <em>/**<em>*</em></em>
<a name="1334" href="#1334">1334</a> <em>     * Provide something useful for debugging purposes.</em>
<a name="1335" href="#1335">1335</a> <em>     *</em>
<a name="1336" href="#1336">1336</a> <em>     * @return some basic information about this instance of LargeSelect.</em>
<a name="1337" href="#1337">1337</a> <em>     */</em>
<a name="1338" href="#1338">1338</a>     <strong>public</strong> String toString()
<a name="1339" href="#1339">1339</a>     {
<a name="1340" href="#1340">1340</a>         StringBuffer result = <strong>new</strong> StringBuffer();
<a name="1341" href="#1341">1341</a>         result.append(<span class="string">"LargeSelect - TotalRecords: "</span>);
<a name="1342" href="#1342">1342</a>         result.append(getTotalRecords());
<a name="1343" href="#1343">1343</a>         result.append(<span class="string">" TotalsFinalised: "</span>);
<a name="1344" href="#1344">1344</a>         result.append(getTotalsFinalized());
<a name="1345" href="#1345">1345</a>         result.append(<span class="string">"\nParameters:"</span>);
<a name="1346" href="#1346">1346</a>         <strong>if</strong> (<strong>null</strong> == params || params.size() == 0)
<a name="1347" href="#1347">1347</a>         {
<a name="1348" href="#1348">1348</a>             result.append(<span class="string">" No parameters have been set."</span>);
<a name="1349" href="#1349">1349</a>         }
<a name="1350" href="#1350">1350</a>         <strong>else</strong>
<a name="1351" href="#1351">1351</a>         {
<a name="1352" href="#1352">1352</a>             Set keys = params.keySet();
<a name="1353" href="#1353">1353</a>             <strong>for</strong> (Iterator iter = keys.iterator(); iter.hasNext();)
<a name="1354" href="#1354">1354</a>             {
<a name="1355" href="#1355">1355</a>                 String key = (String) iter.next();
<a name="1356" href="#1356">1356</a>                 String val = (String) params.get(key);
<a name="1357" href="#1357">1357</a>                 result.append(<span class="string">"\n "</span>).append(key).append(<span class="string">": "</span>).append(val);
<a name="1358" href="#1358">1358</a>             }
<a name="1359" href="#1359">1359</a>         }
<a name="1360" href="#1360">1360</a>         <strong>return</strong> result.toString();
<a name="1361" href="#1361">1361</a>     }
<a name="1362" href="#1362">1362</a> 
<a name="1363" href="#1363">1363</a> }
</pre>
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